Display of backoffice login page when it shouldn't

[Alexenn]

Hello, I've recently moved my prestashop 1.7.3.3 website from one server to another (and one domain to another), I've been able to make it work and to access the backoffice, however I encounter odd displaying of the backoffice login page even if I just logged in and ticked the box to stay connected, sometimes even displaying the connection page two times in a row.

It seems to happen randomly every 2 or 3 (sometimes more) fetching of content, I also encounter it on the translation page in "International > Translations" except this time it was displayed in a frame as you can see in the screenshot attached.

 

There is no javascript error when this login page is loaded, also there is no php error, either on the page or in the logs. I cleared the cache in "Performance", I cleared the cache of LiteSpeed Cache (and deactivated it through the module), and also the one in my browser (chrome) but to no avail.

 

Any idea what could cause this?

Edited May 30 by Alexenn (see edit history)