In 2015 I bought 2 Obi200s from Newegg, one to use with the then PhonePower offer and one for a spare. Last month I ported that number from PhonePower to Google Voice and all I had to do was delete PhonePower from my dashboard and add Google Voice, easy peasy, especially with the excellent advice I got here on the forum from SteveinWa and DrGeof, IIRC. My forum name was Polarfrog in that account.
Yesterday, doom, that Obi died.
I pulled out the spare, connected it and tried adding it for about an hour, but no joy.
I started doing Google searches and reading the forum posts dealing with this problem and knew I was in for a long slog.
After several hours of trying yesterday and into late last night without success I gave up and went to bed.
Got up this morning and started again. I'd made all the recommended changes, adding it to dmz in router, changing DNS via Obi web Portal etc. but none of those tweaks made any difference.
Then this morning I came across 2 recommendations that I think did make the difference.
1. Update the Obi firmware. ***6 was no help, said no update available. But, I came across a post by SteveInWA that included a link to the latest firmware. I downloaded it, went into the Obi web portal and did a manual update.
2. I came across a recommendation that I should sign in with my Google account. When I set up my ObiTalk account in 2015 I just use a non Google email and password. But after seeing that recommendation I signed out and signed back in using "Google Sign In".
Within a few tries my Obi was added to my dashboard and then I was able to add Google Voice right away as SP1.
I'm in no way knowledgeable about Obi or ObiTalk or phone systems in general. I do have some knowledge of computers and am comfortable using them and most software.
I also have no way of quantifying whether the 2 changes I noted above made the difference or not, but I believe they did. So, hope this helps some else.
Thanks to SteveInWA and DrGeof and all the folks who give so much help here on the forum!