I have an Obi1062 and while debugging a different problem I saw "++++ mwi subs failed" many times in the syslog logfile.
Upon investigation I found that one of my service provider entries had Message Waiting Indicator enabled on the Obi but on the Voip.Ms website, that subaccount didn't have a voicemail account associated with it.
Once I added the voicemail box, the problem went away in the logs. Well, I did see it a few time afterwards which might be that their system was unavailable for a few seconds. Still the hundreds of constant messages did disappear.
I had enabled Syslog because I am seeing reboots with no indication of the reason. I'm still looking for that problem.