[Plugin: Multisite User Management] Is there a limit to the number of sites to which a user can be a

I’m trying to add a user to about 250 sites. All sites appear on the list in the settings page, and I selected Editor for each site. I am then prompted to save to edit.php file, which I tried, and only about half the sites are updated with the user. Any suggestions?

https://www.ads-software.com/extend/plugins/multisite-user-management/