Not excepting tester domain when login to perch

Hello

I have entered the development domain as: drcatherinetupper-co-uk.stackstaging.com/ but I keep getting the following message when I try to login: "Sorry, your license key isn't valid for this domain.

Log into your Perch account and add the following as your live or testing domain: drcatherinetupper-co-uk.stackstaging.com".

Could someone please help, Thanks in advance,

Paul