WordPress and multisite: Too_Many_redirects error

What app is this about, and its version: WordPress, 6.9.4
What YunoHost version are you running: 12.1.39
What type of hardware are you using: VPS bought online

Describe your issue

Desired situation: WordPress temporary multisite network on a subdomain, but the interface returns an “err_too_many_redirects” output.
Setup: YunoHost 12.1.39, Debian12, VPS on Hostinger kvm2 package, WordPress 6.9.4.
I read some very old posts here, about this error but they didn’t help me to solve.

How I set it up:
install WordPress on YunoBlog (multisite requires a subdirectory), then flag the “Multisite”
Add a new site from the network admin - english.plusbrothers.net/blog/second
when going to english.plusbrothers.net/blog/second it returns too_many_redirects error.

But, but it goes on regularly, with no errors at all, if I use the second domain I bought just for this year, for testing purposes, plusbrothers.online.

plusbrothers.online/wp and /wp/second work regularly.

is it an issue for subdomains? Because if so, I won’t produce any effort for subdomains and use the .online domain for staging purposes. And then will study another way to transfer all in the main plusbrothers.net which now contains the production site on other provider which I won’t touch for now.
Thanks.

Share relevant logs or error messages

https://paste.yunohost.org/raw/tomovirutu