Unusual session problem

Hi everyone.

We are experiencing an unusual problem with a WordPress instance that was running fine in one AWS VPC. We migrated it to another AWS VPC making minimum changes required to actually move it. I’ll describe what is happening and was wondering if anyone had any ideas. Google searches don’t seem to return any information on anyone else who has experienced this issue.

Wordpress version: 5.0.4
PHP: version 7.1.28
MySQL: version 5.7.21 (RDS)
OS: We have tried both CentOS and Amazon Linux

We tried it with both the original 2 EC instances with the WordPress installation on an EFS file system. At the moment we have just a single instance for troubleshooting purposes.

I log in to the wp-admin page and this works fine. If I just leave it, the login page will pop up telling me my session has expired. But I can normally just close the pop-up and continue clicking without any issues.

I did this while running the web developer plugin on a Chrome incognito window and I can see calls to admin-ajax.php some of which succeed with a response such as:

{“wp-auth-check”:true,”server_time”:1591804972}

And some of which fail with a response such as:

{“wp-auth-check”:false,”server_time”:1591805155}

Any suggestions on how to troubleshoot this issue much appreciated.

Thanks,

Sean Timmins