I used to be able to send and receive calls using VOIP and GMAIL with my N900 but now I can't. Has anyone experienced this and how do I fix it without reflashing?

I am using maemo version 20.2010.36-2maemo14.1.

I have a sip server in my router, which is set up to forward PSTN calls onto my N900. Similarly I can make calls over PSTN from my N900 - At least I could. Now, when I receive calls I get a blue flashing light on the N900 but the phone doesn't ring.

When I try to make a call from the dialing pad, the 'call type' only give me the options for cellular or skype, whereas I used to also have my sip server and gmail accounts.

I have tried enabling and disabling account, and removing and reinstalling these accounts.

My availability shows these accounts as fine, i.e. green.

Any help much appreciated.