What does an exclamation mark mean next to some grades?

[slepselt]

Some grades have a ! next to them. What does this mean?

[bneporadny · Accepted solution]

Hi Susan,

This is caused by #turn it in  It is indicating that there was an error submitting to the similarity service.

[sandra_dihlmann]

How do you remove the exclamation mark so that the grades tally correctly?