Support looked around the system and checked some IIS settings. nothing has changed recently so that couldn't be it. Trying a reboot later this evening to see if it's just "one of those things".
all other EX services are up and running fine for users.

HI Wiser,

You might can try to restart only Query service from EX to see if that helps you by any chance ? It would break Ex Search connections and also affect shortcut retrieval till service is back and running.

Also check if shortcuts are working ?

I saw some weird behaviour is there are some authentication errors logged in application event log due to a password used by IUSER not being in sync.

You have already engaged support so I guess they will evaluate the system and let you know what could be the best course of action.

If restart of server would not fix, i would suggest checking the ports in your firewall 1208 is needed to be opened for web search to work other than port 80.

Thanks,
Rajan

Funny.

This problem happened again, so I searched the KB then went to the forums, only to find this posting started by me.

Restart of Query service and Exchange Manager service resolved this.

HI Wisers,

If it happens on a regular basis speak to EMC Support to find out the root cause and may be another fix

Thanks,
Rajan