Smartthings App...Unable to Add a thing

I purchased 2 GE In-Wall Dimmer Switches (Model: 12727). I was able to connect both switches as a thing within my Smartthing app. But, I had an issue enabling the Smartthing Apps, within the Alexa App.(I was able to turn on/off the lights within Samsung apps, without any issues.) I wasn’t unable to find any help within Amazon to resolve my issue, so I reached out to Samsung Support and ask them to reset my account, then I deleted both apps from my phone. (Smartthings app & Alexa app) I re-installed both apps then logged onto Alexa then I was able to enable the Smartthings Apps successfully. Then I attempted to Add the switches. after 10-15 attempts I was able to add 1 switch and after a few days if attempting I’m still unable to add the second switch.
Any ideas?