This error is pointing to the Billing area of Payments2us where you can get copies of your receipts, update your card and contact details with us.

See: https://help.payments2us.com/m/userguide/l/1386881-billing

To solve this error-

Please Go to Setup  ->Search "Remote Site Settings".  Then locate "AAkonsult" and make sure it is active.

Also, stop/restart the Batch Processor.  See FAQ 1 of How do I start or stop the Batch Processor | Payments2Us - Frequently Asked Questions | Payments2Us Manuals

If the Remote site "AAkonsult" is not there on the list, then please add the Remote site with the Remote Site URL - "https://aakonsult.my.salesforce.com" and Activate it.