Cannot Access Network Admin

I have a multisite install with one subdomain. Honestly at this point I am not really sure when this occurred because it has been an issue for awhile. I can access the main site (1) and subdomain site (2) without any issue, and the site itself functions without issue, but I cannot access the Network Admin Dashboard. Most of the time it is just the white screen of death, but occasionally it will say “Sorry, you do not have permission to access” despite my user account obviously having admin privileges.

I have read other discussions on this topic. Tried disabling plugins, but nothing helps it. Nothing of significance shows up in the error_file. Any other place to look, or direction to go? Thanks.