Greetings! I am experiencing the same issue from the thread here:
The problem is the same issue mentioned in the OP and the suggestion in the post:
I found that issue you experienced is not related to the Membership 2 Pro, but the fact that Multisite with Domain Mapping enabled doesn't allow to cross domain login.
So if your member (which is member on all sites) is logged to Tamana Springs site, he is logged only in Tamana Springs , and not to Lucid allusions.
If user is logged to Lucid allusions, the he is able to do the checkout in store, and the menu shows "Account Logout" as it should be.
You need to enable "Remote Login" in the Domain Mapping option to have cross domain login working.
Worked great. The problem came back when I disabled the plugin then re-enabled the plugin. I am not sure if there were any settings that didn't stay the same or if something was changed or not. However, here is the screenshot on how the settings look.
I also switched stripe payments in memberships to being "live" vs being in "test mode". I'm not sure that would have an effect here tho.
I do need to find a resolve for this right away however! I was notified by a customer and hadn't seen this appear again in testing (before going live with payment).
I hope you can help with this once more, looking forward to your response(s)!
The subsite is lucidallusion.tamanasprings.com (lucidallusion.com as domain map) and the main site is tamanasprings.com
Support access is granted as well!