422 the change you requested was rejected Centos 7

I am getting 422 error on one of my gitlab instances.

OS: CentOS 7 3.10.0-693.2.2.el7.x86_64
GitLab: latest, re-installed twice!
external_url: https://git.datalawn.com
/etc/gitlab/ssl contains the necessary certificate files

The virtual server has 2 virtual processors and 6 GB RAM powered by VirtualMin/CloudMin.

The site does load in SSL mode without a problem but
unable to log in as root or any user and
unable to create a new user.

Please let me know what details you want to see to help me fix this…

Greatly appreciate any help fixing this problem…

Note: I do have another instance of GitLab (https://git.a1z.us) with similar configuration ( on bare metal and lesser RAM) which works just fine.