Log In not working

I am using the free Version 2.7.3 to test drive the plugin. So far so good. except for this recurring problem. It is quite random, appears to happen after I’ve spent a bit of time in the staging environment.

Problem? – I get stuck in a sign in loop. I enter my user name/pw and it tries to resolve them, then the page refreshes and I’m at the sign in page.

I’ve read some help articles on disabling security plug ins and changing various WP settings through cpanel. But they also all refer to then creating a new staging site.

So firstly I am not that good to fully understand the required cpanel changes, secondly I have done quite a bit of work in the staging site, (setting up an online shop) so I don’t want to lose this and start form scratch. I am on WordPress 5.4.2 if that helps.

Is this a bug, does the Pro version eliminate this? Or whats the easiest fix?

Thanks