Good day @questions8,
Thank you for posting to the PayPal community.
Please refer the below guide link :
I would suggest to please process a test payment via card which is not linked to your PayPal account. Since, merchant can't process self payments.
If your still facing any issues, please create a MTS ticket via - https://www.paypal-support.com/s/?language=en_US with the detail information and error details.
If this post or any other was helpful, please enrich the community by giving kudos or accepting it as a solution.