Background callback running correctly (loading animations appearing, print statements appearing too, etc) buut when it finishes it errors out (no output is returned) with this error in the console:

Failed to execute 'setItem' on 'Storage': Setting the value of 'flag_storage' exceeded the quota.

It was resolved by changing the storage_type to 'memory' as per: https://community.plotly.com/t/error-the-quota-has-been-exceeded/26944

Description by the user:

When tested with storage_type = 'memory' instead of 'session', we don’t get the issue, so I tried to understand more why the issue happened only in the past weeks while the storage as session was used for one year on server (Dash Enterprise) and still works in our local machine.
The only difference is that on the server we recently switched from the 2.16.1 version (that we still use on local machine) to the 2.17.1; if we specify dash==2.16.1 even with storage_type='session' we get no issue, but with 2.17.1 we have it.

I don't have additional information and haven't had the opportunity to try to replicate this.