Mender Server 2.5 issue "Please check your connection"

Hi, we had a developer get Mender Server 2.5 up and running on AWS EC2 who is no longer around (so I need to figure out whats going on). For some reason the EC2 server needed to be restarted but now I see all the artifacts we had uploaded have disappeared and we can no longer upload new artifacts. The main clue we have is the notifications on the Server’s Web UI:
“Please check your connection”
“Couldn’t load deployments. Please check your connection Retrying in x seconds”

We had to restart the server in the past an this did not happen.

Any pointers where I should look to resolve this?

*Note the server still seems to find the remote devices and these appear as expected in the “Devices” list.