Then it sounds like
The helixToken expired, since you stored it, and it only has a lifetime of an hour or so (not sure have not chcked)… it’s not designed to be retained, and reused for too long.
So you’d have a user open your extension, extensions calls your EBS with the current helixToken, you use that token to make calls and discard it.
Since each user calling your EBS will call with their own JWT/HelixToken