Error accessing Network Administrator (after cahngeing the main site url)

I wanted to switch the main site between https://www.dentapoint.ro (main site) and a secondary site https://www.dentapoint.ro/2021. I couldn’t change the URL on the main site. After changing in the wp_config blog_ID, I was able to change the URL.
This is where the problem came in. After I changed the site name from dentapoint.ro to dentapoint.ro/old, I can no longer access the network administrator.
https://dentapoint.ro/old/wp-admin is working
https://dentapoint.ro/2021/wp-admin is working
When I try to access de network admin I get db connection error

Please help.

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