profile manager offline post power outage

We recently had a power outage which took out our Mac Mini OD master - on getting it back to life we are unable to open the Profile Manager. when we go to the address, it opens something like the following:-

https://server.tld/auth?redirect=https://server.tld/devicemanagement/webapi/auth entication/callback

...and then times out with the message...

Proxy Error

The proxy server received an invalid response from an upstream server.
The proxy server could not handle the request GET /auth.

Reason: Error reading from remote server

I found that our SSL cert had an issue, which i have re-issued - i am seeing quite a lot of activity in the /var/log/apache2/service_proxy_error.log which i am trying to work out if any of it is relevant to our issue.

Anyone got any thoughts about this... we are