1, the submission deadline has passed.

There is usually a deadline for submitting papers. If you submit it after the deadline, you will definitely not be able to submit it. The editor suggested trying to contact the teacher and negotiate with the teacher to see if it can be submitted backstage.

2. System reasons

There are more people submitting, and if the system load is exceeded, the system will crash, so it keeps showing that it cannot be submitted. The editor suggested that you can contribute during the low peak period.

3. Network reasons

Bad network and network errors can also lead to submission failure. Check the network settings to see if the connection is normal.