When I use the correct token, but return 401 The access token provided is expired

I have a script like this

1. create a token by the user name and password

2.Then use the token to get ticket data

The script runs correctly most of the time

But there are always several errors in a day

HTTP/401: Unauthorized - {"error":"invalid_token","error_description":"The access token provided is expired, revoked, malformed or invalid for other reasons."}

But in fact, when an error occurs, I get the token. I can get the data normally by manually calling the API

Why is this,The token is correct and has not expired, but an error occurred and 401 was returned.This is strange