Error message on launch

Server Version#:1.32.3.7192-7aa441827
Player Version#:

image

As per the details of the message…
Some updates introduce changes to the structure of Plex‘ database. Upgrading from the previous structure can take some time… in order to avoid conflicts by manually interacting with the database while such an upgrade is in progress, Plex is limiting the access to the server for that process.

Usually this is a question of a few minutes max. If you previously skipped a number of upgrades, have a very large library or a rather under-powered server, the process might take longer.