Trying to Build an Alexabot, but trigger words is not working

#1

I am trying to Build an Alexabot, but trigger words is not working. “Alexa, trigger forward.” Is any suggestion on how to get it working. I do not know if this is anyhelp, but I did create my own subdomain. It’s say 502 bad gate for my trigger words.

https://www.dexterindustries.com/projects/alexabot-amazon-alexa-controlled-robot/