When trying to activate the Opayo test account within System Administrator, you can see the following message: 

"Failed to activate the Sage Pay account. The vendor name or password is incorrect, or the account is locked."

You can also find that you’re able to log into the Opayo portal without any issues.

The cause of this error message is due to the Opayo test account and Opayo live account having different passwords. When activating this feature in Sage 200, im assuming 

To resolve this issue, you’ll need to speak to the Opayo support team on 0191 313 0299 and ask them to send out password reset emails.

When you receive these emails, ensure the passwords you create are the same, otherwise the setup will continue to fail.

You’ll then be able to go back into System Administrator and enable Opayo.