Remote login stopped working

Thank you for an amazing plugin. I’ve been using it for a couple of years on many multisites and this is the first issue I’ve ever come across. I appreciate all the time you’ve put into it.

What’s happening is that after a user logs into one of their sub-sites and then navigates to their frontend, the admin bar goes away and they have to relogin.

This only is happening with subsites (using subdomains) that are mapped with this plugin. The ones that use the sub-domain as the primary url work just fine.

I’ve done the standard trouble shooting (deactivating plugins, reverting any code changes since the issues came up, and making setting changes…). Remote login is checked too.

Any ideas what’s going on?

https://wordpress.org/plugins/wordpress-mu-domain-mapping/