Anyone else get error EDS4037 on Apple Watch?

This is not so much a question as just posting my experience with the error and the eventual solution since I couldn’t find any answers online. It may have just been unique to me, but hopefully it’ll save someone else the frustrations I had.

Several months ago my series 4 lost its cellular connection. It appeared to happen after my wife got a series 5 but couldn’t activate it. We called AT&T and they reset something and hers was able to connect. Several days later I noticed mine has lost the connection, saying NO SIM when I checked under cellular on my watch. I tried to add the cellular plan back on through the watch app and but would get the above error. I called AT&T multiple time and after several frustrating failures they sent out a reset of the eSIM on the watch. They were sure that it would fix the problem - it didn’t. The solution I found on my own was that in the My device section of my AT&T account under manage number sync on the phone I was using it still showed as being connected to a number, which I suspect was blocking the watch (with its new eSIM) from joining with the phone. I deactivate the number sync on my phone through the AT&T website then tried activating the cellular connection with the Watch app and it worked.

TLDR:

1 - make sure your phone isn’t still connected to a number sync number in your AT&T account.

2 - have AT&T tech support reset/reissue an eSIM (this process takes 2 hours after they do it)

3 - activate the cellular plan through Watch app.