Hello, @nanastasiou
Please specify, how many images have you tried to import at one time from your Media Library to the Photo Gallery? Maybe you chose too much for import.
Do you experience the same problem if try to import 5 or 10 images?
If the answer is yes – most likely there is a conflict with your other plugin or your theme. We hope you understand that we can’t test our products with all other plugins and themes that are available on the market, and we can’t control the other developers. Therefore bad code of other plugins or templates can provoke a lot of problems.
Please try to deactivate all your plugins one by one and check the issue. Thus you will find out which plugin causes the error. If it won’t help, try to switch temporarily to a standard WordPress theme.
More useful information you can find here: https://supsystic.com/tips-for-solving-issues-faster/
Afterwards let us know about the result. This will help our developers to solve your problem faster.
