diff --git a/src/oidc_test/main.py b/src/oidc_test/main.py
index 8fe32d8..8808562 100644
--- a/src/oidc_test/main.py
+++ b/src/oidc_test/main.py
@@ -306,7 +306,13 @@ async def refresh(
         refresh_token=token["refresh_token"],
         grant_type="refresh_token",
     )
-    await update_token(provider.id, new_token)
+    try:
+        await update_token(provider.id, new_token)
+    except PyJWTError as err:
+        logger.info(f"Cannot refresh token: {err.__class__.__name__}")
+        raise HTTPException(
+            status.HTTP_510_NOT_EXTENDED, f"Token refresh error: {err.__class__.__name__}"
+        )
     return RedirectResponse(url=request.url_for("home"))