I tried 4 or 5 times to "submit booking", after all info had been typed in. I was booted out and much of my info had to be re-typed. Finally after the 4th or 5th time - my booking was accepted.
Also, in some of the fields for number of adults and others, the drop down menu didn't work, or stay on long enough to pick the correct info. The seat selection field never did work for me, but I was able to go direct to the carrier's site (Delta) and select my seats.