diff --git a/api-nei/alembic/versions/b9e4c7f2a1d8_add_oauth_state_table.py b/api-nei/alembic/versions/b9e4c7f2a1d8_add_oauth_state_table.py
new file mode 100644
index 000000000..32c6938a2
--- /dev/null
+++ b/api-nei/alembic/versions/b9e4c7f2a1d8_add_oauth_state_table.py
@@ -0,0 +1,46 @@
+"""Add oauth_state table for server-side PKCE state storage
+
+Revision ID: b9e4c7f2a1d8
+Revises: 3f1a2b4c5d6e
+Create Date: 2026-06-17 00:00:00.000000
+
+"""
+
+from alembic import op
+import sqlalchemy as sa
+
+
+# revision identifiers, used by Alembic.
+revision = "b9e4c7f2a1d8"
+down_revision = "3f1a2b4c5d6e"
+branch_labels = None
+depends_on = None
+
+
+def upgrade() -> None:
+    op.create_table(
+        "oauth_state",
+        sa.Column("state", sa.String(), nullable=False),
+        sa.Column("verifier", sa.String(), nullable=True),
+        sa.Column("nonce", sa.String(), nullable=True),
+        sa.Column("redirect", sa.String(), nullable=True),
+        sa.Column("expires_at", sa.DateTime(), nullable=False),
+        sa.PrimaryKeyConstraint("state", name=op.f("pk_oauth_state")),
+        schema="nei",
+    )
+    op.create_index(
+        op.f("ix_oauth_state_expires_at"),
+        "oauth_state",
+        ["expires_at"],
+        unique=False,
+        schema="nei",
+    )
+
+
+def downgrade() -> None:
+    op.drop_index(
+        op.f("ix_oauth_state_expires_at"),
+        table_name="oauth_state",
+        schema="nei",
+    )
+    op.drop_table("oauth_state", schema="nei")
diff --git a/api-nei/app/api/api_v1/auth/oidc.py b/api-nei/app/api/api_v1/auth/oidc.py
index 83d36e421..e02646820 100644
--- a/api-nei/app/api/api_v1/auth/oidc.py
+++ b/api-nei/app/api/api_v1/auth/oidc.py
@@ -30,6 +30,7 @@
 
 import json
 import secrets
+from datetime import datetime, timedelta
 from typing import Annotated, Any, Optional
 from urllib.parse import quote, unquote
 
@@ -47,6 +48,7 @@
 from app import crud
 from app.api import deps
 from app.core.config import settings
+from app.models.oauth_state import OAuthState
 from app.models.user import User
 from app.models.user.user_email import UserEmail
 from app.schemas.user import ScopeEnum, UserCreate
@@ -88,7 +90,7 @@
 # ---------------------------------------------------------------------------
 
 _STATE_COOKIE = "oauth_state"
-_STATE_MAX_AGE = 600  # 10 minutes
+_STATE_MAX_AGE = 1800  # 30 minutes — enough time for slow email delivery
 
 
 def _signer() -> URLSafeTimedSerializer:
@@ -103,6 +105,7 @@ def _set_state_cookie(
     redirect_to: Optional[str] = None,
     user_id: Optional[int] = None,
     code_verifier: Optional[str] = None,
+    db: Optional[Session] = None,
 ) -> None:
     payload: dict = {"s": state}
     if oidc_nonce:
@@ -121,29 +124,82 @@ def _set_state_cookie(
         samesite="lax",
         max_age=_STATE_MAX_AGE,
     )
-
-
-def _verify_and_pop_state_cookie(request: Request, response: Response, state: str) -> dict:
+    if db is not None:
+        try:
+            db.query(OAuthState).filter(OAuthState.state == state).delete()
+            db.add(OAuthState(
+                state=state,
+                verifier=code_verifier,
+                nonce=oidc_nonce,
+                redirect=redirect_to,
+                expires_at=datetime.utcnow() + timedelta(seconds=_STATE_MAX_AGE),
+            ))
+            db.commit()
+        except Exception:
+            db.rollback()
+            logger.warning("Failed to persist OAuth state to DB — cookie-only fallback applies")
+
+
+def _verify_and_pop_state_cookie(
+    request: Request,
+    response: Response,
+    state: str,
+    *,
+    db: Optional[Session] = None,
+) -> dict:
     cookie_val = request.cookies.get(_STATE_COOKIE)
     response.delete_cookie(_STATE_COOKIE, httponly=True, samesite="lax")
 
-    if not cookie_val:
-        raise HTTPException(status.HTTP_401_UNAUTHORIZED, "Missing OAuth state cookie")
-
-    try:
-        payload = _signer().loads(cookie_val, max_age=_STATE_MAX_AGE)
-    except SignatureExpired:
-        raise HTTPException(status.HTTP_401_UNAUTHORIZED, "OAuth state expired — please try again")
-    except BadSignature:
-        raise HTTPException(status.HTTP_401_UNAUTHORIZED, "Invalid OAuth state")
-
-    # Constant-time comparison; also handle the pre-migration "n" key for
-    # cookies issued by the previous version of this code.
-    stored = payload.get("s") or payload.get("n")
-    if not stored or not secrets.compare_digest(stored, state):
-        raise HTTPException(status.HTTP_401_UNAUTHORIZED, "OAuth state mismatch")
-
-    return payload
+    if cookie_val:
+        try:
+            payload = _signer().loads(cookie_val, max_age=_STATE_MAX_AGE)
+        except SignatureExpired:
+            raise HTTPException(status.HTTP_401_UNAUTHORIZED, "OAuth state expired — please try again")
+        except BadSignature:
+            raise HTTPException(status.HTTP_401_UNAUTHORIZED, "Invalid OAuth state")
+
+        # Constant-time comparison; also handle the pre-migration "n" key for
+        # cookies issued by the previous version of this code.
+        stored = payload.get("s") or payload.get("n")
+        if not stored or not secrets.compare_digest(stored, state):
+            raise HTTPException(status.HTTP_401_UNAUTHORIZED, "OAuth state mismatch")
+
+        if db is not None:
+            try:
+                db.query(OAuthState).filter(OAuthState.state == state).delete()
+                db.commit()
+            except Exception:
+                db.rollback()
+
+        return payload
+
+    # Cookie missing (e.g. callback arrived in a different browser after email
+    # verification). Try the DB-backed state as a fallback.
+    if db is not None:
+        row = db.query(OAuthState).filter(OAuthState.state == state).first()
+        if row and row.expires_at > datetime.utcnow():
+            payload = {"s": row.state}
+            if row.nonce:
+                payload["n"] = row.nonce
+            if row.redirect:
+                payload["r"] = row.redirect
+            if row.verifier:
+                payload["v"] = row.verifier
+            try:
+                db.delete(row)
+                db.commit()
+            except Exception:
+                db.rollback()
+            return payload
+
+    raise HTTPException(status.HTTP_401_UNAUTHORIZED, "missing_state_cookie")
+
+
+def cleanup_expired_oauth_states(db: Session) -> int:
+    """Delete expired OAuthState rows. Returns the number of rows deleted."""
+    deleted = db.query(OAuthState).filter(OAuthState.expires_at < datetime.utcnow()).delete()
+    db.commit()
+    return deleted
 
 
 # ---------------------------------------------------------------------------
@@ -508,6 +564,7 @@ def _login_error_redirect(code: str) -> RedirectResponse:
 )
 async def oidc_login(
     response: Response,
+    db: DbSession,
     redirect_to: Optional[str] = None,
 ):
     _require_oidc()
@@ -542,6 +599,7 @@ async def oidc_login(
         oidc_nonce=oidc_nonce,
         redirect_to=safe_redirect,
         code_verifier=auth_url_data.get("code_verifier"),
+        db=db,
     )
     return redirect_response
 
@@ -562,7 +620,7 @@ async def oidc_callback(
 ):
     _require_oidc()
 
-    state_payload = _verify_and_pop_state_cookie(request, response, state)
+    state_payload = _verify_and_pop_state_cookie(request, response, state, db=db)
     raw_redirect = state_payload.get("r")
     redirect_to = raw_redirect if _is_safe_redirect(raw_redirect) else None
     code_verifier = state_payload.get("v")
@@ -626,9 +684,17 @@ async def oidc_callback(
             raise
         error_code = {
             status.HTTP_403_FORBIDDEN: "unverified",
-            status.HTTP_401_UNAUTHORIZED: "session",
             status.HTTP_400_BAD_REQUEST: "invalid_response",
-        }.get(e.status_code, "unknown")
+        }.get(e.status_code)
+        if error_code is None:
+            if e.status_code == status.HTTP_401_UNAUTHORIZED:
+                error_code = (
+                    "email_verified_relogin"
+                    if getattr(e, "detail", "") == "missing_state_cookie"
+                    else "session"
+                )
+            else:
+                error_code = "unknown"
         logger.info(f"OIDC callback failed ({e.status_code}): {e.detail}")
         return _login_error_redirect(error_code)
     except httpx.HTTPError as e:
diff --git a/api-nei/app/main.py b/api-nei/app/main.py
index a61cafa20..457cd51d3 100644
--- a/api-nei/app/main.py
+++ b/api-nei/app/main.py
@@ -5,8 +5,11 @@
 from fastapi.middleware.cors import CORSMiddleware
 from fastapi.responses import ORJSONResponse
 
+from loguru import logger
+
 from app.api.api_v1 import router as api_v1_router
 from app.db.init_db import init_db
+from app.db.session import SessionLocal
 from app.core.logging import init_logging
 from app.core.config import settings
 from app.core.extension_scopes import load_scopes_from_manifests
@@ -21,6 +24,18 @@ async def lifespan(_: FastAPI):
     load_scopes_from_manifests()
     # Update OAuth2 scheme with extension scopes
     dynamic_oauth2_scheme.update_scopes()
+    # Remove OAuth state rows left over from previous sessions
+    try:
+        from app.api.api_v1.auth.oidc import cleanup_expired_oauth_states
+        db = SessionLocal()
+        try:
+            n = cleanup_expired_oauth_states(db)
+            if n:
+                logger.info(f"Cleaned up {n} expired OAuth state row(s) on startup")
+        finally:
+            db.close()
+    except Exception:
+        logger.warning("OAuth state cleanup on startup failed — continuing")
     yield
 
 
diff --git a/api-nei/app/models/__init__.py b/api-nei/app/models/__init__.py
index fffcf8a87..75cb956ac 100644
--- a/api-nei/app/models/__init__.py
+++ b/api-nei/app/models/__init__.py
@@ -1,3 +1,4 @@
+from .oauth_state import OAuthState
 from .user import User
 from .event import Event
 from .faina import FainaMember, FainaRole, Faina
diff --git a/api-nei/app/models/oauth_state.py b/api-nei/app/models/oauth_state.py
new file mode 100644
index 000000000..be83115e1
--- /dev/null
+++ b/api-nei/app/models/oauth_state.py
@@ -0,0 +1,13 @@
+from datetime import datetime
+from sqlalchemy import Column, DateTime, String
+from app.db.base_class import Base
+
+
+class OAuthState(Base):
+    __tablename__ = "oauth_state"
+
+    state = Column(String, primary_key=True)
+    verifier = Column(String, nullable=True)
+    nonce = Column(String, nullable=True)
+    redirect = Column(String, nullable=True)
+    expires_at = Column(DateTime, nullable=False)
diff --git a/web-nei/src/pages/auth/Login/index.jsx b/web-nei/src/pages/auth/Login/index.jsx
index afc096f7d..b1bb1d24a 100644
--- a/web-nei/src/pages/auth/Login/index.jsx
+++ b/web-nei/src/pages/auth/Login/index.jsx
@@ -6,6 +6,12 @@ import config from "config";
 // Error codes surfaced by the backend's oidc_callback. Keep in sync with
 // _login_error_redirect in api-nei/app/api/api_v1/auth/oidc.py.
 const ERROR_COPY = {
+  // success:true renders a green notice instead of the default error card
+  email_verified_relogin: {
+    title: "Your account is verified!",
+    body: "Your email was confirmed successfully. Sign in to continue.",
+    success: true,
+  },
   unverified: {
     title: "Verify your email to continue",
     body: "We sent you a verification link. Check your inbox (and spam folder), click the link, and come back to sign in.",
@@ -61,13 +67,13 @@ export function Component() {
       : "/auth/login";
     return (
       <div className="flex h-screen items-center justify-center p-6">
-        <div className="card w-full max-w-md bg-base-100 shadow-xl">
+        <div className={`card w-full max-w-md shadow-xl ${copy.success ? "bg-success/10 border border-success" : "bg-base-100"}`}>
           <div className="card-body items-center text-center">
-            <h2 className="card-title text-2xl">{copy.title}</h2>
+            <h2 className={`card-title text-2xl ${copy.success ? "text-success" : ""}`}>{copy.title}</h2>
             <p className="py-2 text-base-content/80">{copy.body}</p>
             <div className="card-actions mt-4">
-              <Link to={retryHref} className="btn btn-primary" replace>
-                Try again
+              <Link to={retryHref} className={`btn ${copy.success ? "btn-success" : "btn-primary"}`} replace>
+                {copy.success ? "Sign in" : "Try again"}
               </Link>
             </div>
           </div>