Our phone system did the same thing and it was a Denial of Service attack causing the system to shut down at least once per day. Not sure what your options are without a contract but if you had an active support contract they will honor it through 2019 if I remember correctly.
Interesting idea. I wouldn't doubt that is happening to us here. The other day both phone systems were acting strange on the webui side. My 370 just has more CPU to handle it i'd bet.
I wish they gave us a tcpdump utility...
I tried tried re-upping my subscription when they said they were ending support, but it was too late. I'd gladly throw money at them, but even support just shrugged at every BPS issue we called in with at the end.
In the end, this phone system only handles a fax line and single extension. My other system has 50 users on it. I can just move her to my 370, the 170 is extremely underpowered, with boot taking 10+ minutes since I pulled it out of the box new.