yes, there is a read replica, however using the writer end-point for the db connection
The error messages appear on the webpage, after input of the authentication details on the GitLab SSO page, Mattermost will return one of those error messages, but cant determine which when.
I checked the session table in the DB, cleared it out, tried some connect. Sometimes, I see entries being written there, but still one of those errors appear, and does not proceed.
Interesting, to note, is that could still post messages to the API, and get email notification from Mattermost, so seems everything else is working, apart from the SSO authentication token portion