Oops! something went wrong while processing your order – error

Does the error message appear within the bpost iframe ?

Yes, here is a screen shot. Anyway you can check it yourself on a website.
https://www.moai.pl/bpost.jpg

sorry, here is screen shot with actual error
https://www.moai.pl/bpost2.jpg

Hello,

This problem is due to the fact that no Default address is chosen for the sender, as explained in the following link:

https://bpost.freshdesk.com/support/solutions/articles/4000070401-prerequisites-configuration-default-sender-address-and-price-range-configuration

When you Edit one of the addresses into default and save this, the problem should be solved.

Kind regards

Thanks, it’s working now :]