Hello,
Thank you for your post on the PayPal Merchant Technical Support Community.
I have seen this error message with the following:
Incorrect Sandbox credentials
Confirm that you are using the correct Sandbox Credentials and that you are pointed to sandbox and not production
Sandbox email address is not confirmed
Log into your Sandbox account https://sandbox.paypal.com and click on the account settings icon next to the log out
Click on Your Profile
Click on update next to your email address
Make sure it is confirmed
The Sandbox account is locked or closed
Make certain that you can log into the sandbox account and that you do not see any notifications that the account is locked or closed
Thank you,
Jennifer
PayPal
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