Getting "##api.submissions.unknownError##" when I want to delete a submission as both administrator, editor

In OJS 3.1.0, I get “##api.submissions.unknownError##” when I want to delete a submission (a test submission). As I am moving from OJS 2 to OJS 3, I am afraid to run into further problems? any idea what kind of error is and how this error is generated? how can I fixed it or

Hi @rmosavi,

Check your PHP error log for details.

Regards,
Alec Smecher
Public Knowledge Project Team

Though a long time passed. We did try php-error log there was no error. We have another problem with assigning role to our user the only role that works is journal editor. what kind of problem are we faced?? you have any idea?