diff --git a/internal/controller/oauth_controller.go b/internal/controller/oauth_controller.go
index 1aec73ae..e72c09fd 100644
--- a/internal/controller/oauth_controller.go
+++ b/internal/controller/oauth_controller.go
@@ -208,7 +208,12 @@ func (controller *OAuthController) oauthCallbackHandler(c *gin.Context) {
 		name = user.Name
 	} else {
 		controller.log.App.Debug().Msg("No name from OAuth provider, generating from email")
-		name = fmt.Sprintf("%s (%s)", utils.Capitalize(strings.Split(user.Email, "@")[0]), strings.Split(user.Email, "@")[1])
+		parts := strings.SplitN(user.Email, "@", 2)
+		if len(parts) == 2 {
+			name = fmt.Sprintf("%s (%s)", utils.Capitalize(parts[0]), parts[1])
+		} else {
+			name = utils.Capitalize(user.Email)
+		}
 	}
 
 	var username string
diff --git a/internal/controller/oidc_controller.go b/internal/controller/oidc_controller.go
index 142f0b40..e46e7e82 100644
--- a/internal/controller/oidc_controller.go
+++ b/internal/controller/oidc_controller.go
@@ -146,7 +146,7 @@ func (controller *OIDCController) Authorize(c *gin.Context) {
 	client, ok := controller.oidc.GetClient(req.ClientID)
 
 	if !ok {
-		controller.authorizeError(c, err, "Client not found", "The client ID is invalid", "", "", "")
+		controller.authorizeError(c, fmt.Errorf("client not found: %s", req.ClientID), "Client not found", "The client ID is invalid", "", "", "")
 		return
 	}
 
@@ -288,7 +288,7 @@ func (controller *OIDCController) Token(c *gin.Context) {
 		entry, err := controller.oidc.GetCodeEntry(c, controller.oidc.Hash(req.Code), client.ClientID)
 		if err != nil {
 			if err := controller.oidc.DeleteTokenByCodeHash(c, controller.oidc.Hash(req.Code)); err != nil {
-				controller.log.App.Error().Err(err).Msg("Failed to delete code")
+				controller.log.App.Error().Err(err).Msg("Failed to revoke tokens for replayed code")
 			}
 			if errors.Is(err, service.ErrCodeNotFound) {
 				controller.log.App.Warn().Msg("Code not found")
diff --git a/internal/service/auth_service.go b/internal/service/auth_service.go
index a721aa2b..925c2951 100644
--- a/internal/service/auth_service.go
+++ b/internal/service/auth_service.go
@@ -773,46 +773,49 @@ func (auth *AuthService) ensureOAuthSessionLimit() {
 	auth.oauthMutex.Lock()
 	defer auth.oauthMutex.Unlock()
 
-	if len(auth.oauthPendingSessions) >= MaxOAuthPendingSessions {
-
-		cleanupIds := make([]string, 0, OAuthCleanupCount)
+	if len(auth.oauthPendingSessions) <= MaxOAuthPendingSessions {
+		return
+	}
 
-		for range OAuthCleanupCount {
-			oldestId := ""
-			oldestTime := int64(0)
+	type entry struct {
+		id        string
+		expiresAt int64
+	}
 
-			for id, session := range auth.oauthPendingSessions {
-				if oldestTime == 0 {
-					oldestId = id
-					oldestTime = session.ExpiresAt.Unix()
-					continue
-				}
-				if slices.Contains(cleanupIds, id) {
-					continue
-				}
-				if session.ExpiresAt.Unix() < oldestTime {
-					oldestId = id
-					oldestTime = session.ExpiresAt.Unix()
-				}
-			}
+	entries := make([]entry, 0, len(auth.oauthPendingSessions))
+	for id, session := range auth.oauthPendingSessions {
+		entries = append(entries, entry{id, session.ExpiresAt.Unix()})
+	}
 
-			cleanupIds = append(cleanupIds, oldestId)
+	slices.SortFunc(entries, func(a, b entry) int {
+		if a.expiresAt < b.expiresAt {
+			return -1
 		}
-
-		for _, id := range cleanupIds {
-			delete(auth.oauthPendingSessions, id)
+		if a.expiresAt > b.expiresAt {
+			return 1
 		}
+		return 0
+	})
+
+	for _, e := range entries[:OAuthCleanupCount] {
+		delete(auth.oauthPendingSessions, e.id)
 	}
 }
 
 func (auth *AuthService) lockdownMode() {
 	ctx, cancel := context.WithCancel(context.Background())
-	defer cancel()
-	auth.lockdownCtx = ctx
-	auth.lockdownCancelFunc = cancel
 
 	auth.loginMutex.Lock()
 
+	if auth.lockdown != nil && auth.lockdown.Active {
+		auth.loginMutex.Unlock()
+		cancel()
+		return
+	}
+
+	auth.lockdownCtx = ctx
+	auth.lockdownCancelFunc = cancel
+
 	auth.log.App.Warn().Msg("Too many failed login attempts, entering lockdown mode")
 
 	auth.lockdown = &Lockdown{
@@ -825,10 +828,12 @@ func (auth *AuthService) lockdownMode() {
 	auth.loginAttempts = make(map[string]*LoginAttempt)
 
 	timer := time.NewTimer(time.Until(auth.lockdown.ActiveUntil))
-	defer timer.Stop()
 
 	auth.loginMutex.Unlock()
 
+	defer cancel()
+	defer timer.Stop()
+
 	select {
 	case <-timer.C:
 		// Timer expired, end lockdown
diff --git a/internal/service/oauth_service.go b/internal/service/oauth_service.go
index 0def3143..dc0b7c08 100644
--- a/internal/service/oauth_service.go
+++ b/internal/service/oauth_service.go
@@ -26,6 +26,7 @@ func NewOAuthService(config model.OAuthServiceConfig, id string, ctx context.Con
 		Transport: &http.Transport{
 			TLSClientConfig: &tls.Config{
 				InsecureSkipVerify: config.Insecure,
+				MinVersion:         tls.VersionTLS12,
 			},
 		},
 	}