I can't add extensions to the site, what could be the problem?

Question

opencart

The site uses a synchronization module with 1C, redirecting to https
Tried this: https://opencartforum.com/topic/44939-resheno-zagr...
Did not help...
Version 2.3

Answer 1

if you install a modifier, then it must end with ocmod.xml, if the archive, then with ocmod.zip

Answer 2

If ftp is not configured in the admin panel, put a fix