Can’t login to subdomains after SSL was turned on

Hello,

In brief. At https://www.example.com I have multisite installation of WordPress. I can log in there and it works OK. But I have also few other domains connected to it. Let we say https://www.example1.com and https://www.example2.com where I can’t login.

I read this: https://www.ads-software.com/support/article/login-trouble/ but these things doesn’t help. I think it could be connected to switch from http to https which I done some time ago (before that I was able to login) but I don’t know where to look for solution.

I use Let’s Encrypt certifcates from my domains operator. In his panel there are only two options “Install Let’s Encrypt certifcate” or not. There is nothing to screw up ?? I also installed Relly simply SSL plugin.

What I can do? ??