If you are using the comma then that is definitely the problem.

I did try using the ebay label printing service as it is annoying having to log out of one account with click & send to log into another id if you only have one label to print but I will never use it again, it printed on more than a quarter of the page so instead of being able to get 4 labels out of an A4 sheet of paper I could only get one.

Back to the click & send site for me even if it is for a single label.

Another advantage of c&s is that I can click on validate next to the address before I go any further so can sort out any issues first before trying to select a service and getting thrown back.