Membership 2 showing active memberships as being expired

We recently migrated to a new server and theme. We have had problems with the M2 plugin in the past and are continuing to have problems. Here are some of the experiences our users have sent in:

"I just tried to sign up a one year membership on your new website and it timed out three times in a row. I tried to log in using my email and what I thought was my password with no luck. I would really like to get this done and get access, help."

"clicked the link for 12 month subscription, after the wheels spin for a bit, I eventually get a server not responding error message."

I have tested the membership signup process using Stripe Single Gateway in test mode and did not encounter any issues with the pages timing out.

Other users are able to log in with their correct username and passwords, but have no access to protected content. Within the admin, their subscription status is listed as "Pending (activate on next payment)" In each case, the expiration is set for next year. If we change this status to "Activated" and click Save Changes on the Edit Member admin page, nothing changes. The status still shows "Pending (activate on next payment)"

Query Monitor is installed for your use (currently deactivated)
Wordfence is also installed and there is useful information under Wordfence > Tools > Diagnostics, for you to view the environment setup and variables being used.

I have granted support access to our site, and created a test user which exhibits the expiration issue: JeremySub

My questions are:

1) How can we resolve this "Pending (activate on next payment)" issue?
2) How can we resolve this timeout issue during signup? -- our site contains 2,321 posts and have had issues in the past where M2 will generate over 15,000 DB queries on page loads. This is the only experience with M2 that I have seen create exceedingly long load times which could cause timeout errors. Our current PHP limit settings are memory_limit: 2148M, and max_execution_time: 60.

Seeing as we have recently taken our updated site live, you can see how this is a time sensitive issue for us. We need to be able to process new and existing memberships.

Thank you for your assistance; please let me know if I can provide any more information.