SmartThings WiFi plug won't connect to my account

I’m trying to add a SmartThings WiFi plug to my existing devices. It connects to my WiFi without any problem and continues, but when it says connecting to my account it just eventually times out. I have tried this on my Samsung Phone (Android) and on my Samsung tablet (Android) several times.

I have 2 others of this exact plug that have been working for a long time, but I cannot get this one completely set up because it always hangs trying the final step to connect to my account. I have the most recent available app from the Play Store so I don’t understand why it isn’t working. The error code is 15-200.

Any suggestions?

try rebooting your router

I forgot to mention that was one of the suggestions in the smart things app help section that I tried. It didn’t help.