When I try to schedule an inspection I receive a message, "the inspection is already scheduled." What does this mean?

The inspection you are requesting is already scheduled for that day or a previous inspection request has not been completed.

1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.