Originally Posted by
BingBongBoy
Sorry to bring this thread up again... But, I am having the same issue adding LH Miles and More number to an existing reservation...
Everything else works, and I have double and triple checked my number from LH, copy and paste it also, but just refuses to accept it with the same error message as the OP is/was getting.
Try using the TG App. Try changing the location on the TG website (some country sites appear to have different implementations).
Try using the LH or other *A website.
Call or email TG. Or finally, do during OLCI.