Identical routers with OpenVPN but only one works

[billpnola]

Hello
I have identical Trendnet TWG-431BR routers at two different locations.

They each are configured as static IP routers, and each work fine in that sense.
Here is what I cannot figure out…

Router 1-I can connect to it remotely via OpenVPN, whether it be via IOS or Windows. No problem.
It is connected to a Cox Cable internet service with a static IP address.

Router 2- I cannot!
It is connected to AT&T Fiber service with a static IP address.

Can someone help me troubleshoot this issue?

Thank you in advance.
Bill