Hello Welcome to eBay SignIn Oops, that's not a match.

[818-tech]

Good morning,

When I try to connect I have 

Hello

Welcome to eBay SignIn

Oops, that's not a match.

here: signin.sandbox.ebay.com

[developer_support@ebay]

Hi @818-tech 

You can try to reset your Sandbox password on Reset Sandbox User Password page and try again to login

for the Sandbox account. 

Please make sure to use the TESTUSER_ prefix with your sandbox username.