Hi experts,

Today I’ve updated my multisite to WP 5.6, then I lost the access to the site. Each site, network backend, the backends for each site got into 302 loop.

What I’ve tried for far are;
– clearing the cache
– private mode browser
– renaming all the plugin files
– renaming the active Theme file
– Go back to WP 5.5 via FTP

And after reading this thread,
https://wordpress.org/support/topic/wp-multisite-too-many-redirects-on-wp-admin/
I also tried disabling SSL for the meantime, that ended up nginx error.

Actually, restoring the backup with 5.5 worked fine. However I need to know what caused this issue in order to keep up with the future WordPress versions.

Any help would be highly appreciated!!

Regards,

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