Error while trying to update to 1.6.25

Hi everyone :wave:t3:

I successfully installed and started to use Grav this afternoon, it’s incredibly easy and powerful, I love it already!

I searched the forum but I could not find any similar issue so I’m posting here.
I experienced an issue while trying to update from 1.6.23 to 1.6.25 (I installed it from softaculous on my cpanel host), I’m getting an error message “AJAX ERROR” and
here is the other error message
Screen Shot 2020-05-22 at 23.42.58|690x49

Also, second issu that might be related, I can’t download any Theme, I also get an error message.

I tried to use the http and https route, but the same issue keeps happening.

Did someone already experienced the same?

Thanks in advance for your help,
Arthur