custom url

Oh, I need help. 🙁
After changing the links from example.com to example.com/communications The site works, the backend of each site works, but when I want to access the network of multi site https://example.com/communications/wp-admin/network/ it returns me the error “example.com redirected you too many times”.

But when i want’t to access the link to the plugin UpdraftPlus Backup/Restore https://example.com/communications/wp-admin/network/settings.php?page=updraftplus&tab=status it works again.

Why the link wp-admin/network/settings.php?page=updraftplus&tab=status it works and the link wp-admin/network/ not? 🙁

Please help.