Phone Manager use results in "System Incompatibility" on 5610SW IP

[mdegray]

I've set up a user with Phone Manager 3.1.17 to log into an IP extension on our 406v2 (3.1.65). No errors are reported when starting PM, but it takes several attempts before a successful call is made (the dial window clears and nothing happens), and when that finally happens, the base extension displays "System Incompatibility". It does not return to a useable state even when PM is closed and must be reloaded to return it to service. Sometimes (not always) the phone comes back up saying "extension in use". As usual, a search of Avaya's site yields nothing. So, 2 questions: 1. What would prevent PM from working properly upon first starting. 2. Is the IP phone behaviour normal? This happens on all IP extensions I've tried.

TIA
mike

 

[IPOUK]

Is PM set to Voip mode?

 

[mdegray]

Yes. In fact, I've stepped meticulously through the setup docs.

 

[IPOUK]

It's a big grey area - if the phone hasn't logged out, you can't use the same extn to login over it with a SoftPhone. A real pain and something Avaya just don't give a whole lot of information about.