cannot access admin page

Hello
I am facing the following problem: If I try to change the admin language from English to Greek then I cannot access the admin page and I get the following error:
The web page at https://www.mydomain.gr/admin/index.php ... vn576y30K1 might be temporarily down or it may have moved permanently to a new web address. ERR_CONTENT_DECODING_FAILED

The site is working ok without any issues only at admin page i get the error
Any idea why this is happening? Opencart version 2.3.0.2
Thank you in advance

You can simply google for solution (plenty of them):

https://www.google.com/search?q=ERR_CON ... ING_FAILED

The problem was from the compression level, I change it from 7 to 0 and it is working ok.