Check-in and notes not working via SMS

I have not been able to check-in or post notes via SMS for at least two days.

Check-in results in no response. Posting notes ALSO resulted in no response, until I removed and re-added my mobile number.

I received and replied to the text message to verify my number, but mobile check-in is still not working.

Since re-adding my mobile number, any attempt to post a note results in the following reply:

"Sorry but you must be checked in at a place to post notes..."

I HAVE checked-in since re-adding my mobile number. I did so via the Web, since mobile check-in is not working. I still get the above message when attempting to post notes via SMS. This only started after I re-added my mobile number. Prior to that, I would get no response, and the note would not post.

Mobile check-in does not work at all, and results in no error message.