I had one this morning like that. Then I noticed it was a 24-hour sweep and I figured my 24-hours had not been up yet in order to enter it again.
Sometimes it has nothing to do with you but with the sweep. Like a glitch or technical problem. Sometimes it's because the form wants you to manually type in that specific data. For instance, if it comes back where there was an error with my zip, I'll manually type it in and then it'll submit.
Try doing the city, state, and zip manually if that happens. Either type in the info or manually choose it from the drop-down box, whichever.