I got help from ST support; what they had me to do was open settings on my phone, Apps, Application manager, Amazon Alexa, storage then clear data, force stop Alexa and re-sign in; disable ST skills then enable ST skills i was good to go.
Again thanks for all your help.
WB40, I am having an issue where Alexa will no longer discover devices on my SmartThings Hub. Above you mentioned for the OP to stop if there was more than one location (I have two locations and two Amazon accounts). Does this cause a problem with Alexa? I have been on support with both Samsung and Amazon and neither has been able to resolve the issue. Thanks, JW