New multisite install – can’t access Network Admin

Hello!

Have you tried using generic link repair plugins to at least identify your issue and where its coming from?

There is a possibility that you may need to do a search and replace with your database.

or try to atleast get more details on your current situation by perhaps starting with getting a list of broken links?

You can use this:

Broken Link Checker:
https://wordpress.org/plugins/broken-link-checker/

then use this plugin to try and do an immediate easy fix:

Better Search and Replace:

https://wordpress.org/plugins/better-search-replace/

Hope these help.