Paypal express error "unable to place the order" when returning to website after payment
I'm running a website based on ver. 2.1.3. We never had a problem with the paypal payment until this week, when 2 customers had problems with it.
When making the order, customers are getting redirected to paypal to make the payment. After all is done and the payment done, instead of going to the "success" page, customers are redirected to the cart, and a "unable to place the order" error is shown.
I checked the logs and i couldnt find anything related to that error.
I tried making the configuration of the module again, but it didn't work. So if nothing is shown in the logs... i dont know where to start.
Are there specific Paypal logs anywhere?
This post from 2015 seems to have the same problem...