There is a pop up with a notification appearing ''Incomplete value'', What does it mean?

And there is a pop up with a notification appearing ''Incomplete value'', What does it mean?

Generally, this error message is displayed when the form is submitted while there are any required fields are not filled. I have tried sending a test submission to your form and I was not able to replicate the issue at my end. If you are still experiencing any issue, please let us know. We will be happy to take a look again.