When posting and asking for assistance, more information is always best.
What website are you experiencing this issue? Comcast? Call them.
What browser are you using? Have you tried clearing the cache?
I am getting the same message
SH400.203: Invalid Token
when trying to setup a payment for a future date on the xfinity site. I am adding my credit card#....
I'm getting the same error message as well when trying to pay my bill. I've used two different browers -- Google Chrome and Microsoft Edge and still no luck.
I have escalated this thread - hopefully we'll get an answer soon.
Typically invalid tokens are caused from an error in Two step authentication or even an IP address change.
Please clear your cache and cookies to resolve this.
as a Software Engineer with as little as six years of experience, let me be the first to tell you, that never in the history of any company did I ever work for did someone turn around and tell the customer that it was their fault and to use a different tool if a service like this one did work. YOU, and I mean YOU take responsability and build something robust that works all the way back to IE6-use sancha if you have to. Don't tell the customer that they need to clear cache or use a different browser. That's called being lazy and now wanting to spend money on the tool that LITERALLY keeps the cashflow and lights on.