I have the same problem with a version 3.7 installed few weeks ago (about 6 to 8 weeks). Brand new system. I will post later the NT7B. It's happend only twice. Everytime costumer call first hour in the morning. Happend during night. First time, we got power outage during the night but we had a battery backup maybe the battery runout of power. I don't know but, last week nothing special. The costumer call to let us know that voice mail is down and also the wireless phone (WLAN2211 set). No PBX found on the handset. I log on remotely. Yes I have access to ! On backup section I'm able to restart system. Everything work fine after restart but never know when it will happend again. I will take a look at my backup schedul. I will let you know !
I sure that the version 3.7 are no cover by PAA for replacing the MSC card. It's affect only version 3.0, 3.01 & 3.5