Progress bar does not close when calling asynchronous microflow

Enabled asynchronous calling on a microflow button, and a non-blocking progress bar. The progress bar is automatically closed, when the jobs is finished in about 1 minute. However when the job is taking about 5 minutes, then the progress bar is not closed. Anyone familiar with this issue?
1 answers

I have previously encountered this issue with a user working from within a corporate network where their firewall did not like this. Could this be some type of firewall issue as well?