Make sure your C-Name record points to qr.webapp-portal.com or your A-Record to 188.8.131.52.
Please always use C-Names instead of A-Records.
In case you are not able to set a C-Name use an A-Record at your own risc.
(If our server's ip address changes to a new one the A-Record is not working anymore and you have to correct the record manually)
If you have a white label account, you might have changed your production url.
In that case an email has been sent to you with the new url and login credentials.