Expired tokens do not get refreshed

[marblestation]

Expected Behavior

When an access token has expired, it should be refreshed. Here is a python example of what is required to refresh a token.

Actual Behavior

When an access token has expired, it keeps calling bootstrap at a very fast pace.

Steps to Reproduce

This is not easy to reproduce since it requires an expired access token, which eventually can be obtain while this issues is not fixed: adsabs/adsws#156