diff --git a/src/lib/server/auth.ts b/src/lib/server/auth.ts
index 76b9f8bf0ac..c30b885bb26 100644
--- a/src/lib/server/auth.ts
+++ b/src/lib/server/auth.ts
@@ -95,7 +95,7 @@ async function getOIDCClient(settings: OIDCSettings): Promise<BaseClient> {
 		client_secret: OIDConfig.CLIENT_SECRET,
 		redirect_uris: [settings.redirectURI],
 		response_types: ["code"],
-		[custom.clock_tolerance]: OIDConfig.TOLERANCE || undefined,
+		[custom.clock_tolerance]: Number(OIDConfig.TOLERANCE) || undefined,
 	});
 }