Automation Anywhere File Trigger failure

Question

I set a file trigger for my robot, but it does not function. Concretely speaking, if a person puts a file (any file) in the assigned folder, the robot is supposed to start working. However, the robot is not working. This happens frequently. For now, to fix it, restart PC is needed.

In case you know what is happening to my dear robot,

please tell me how to fix the issue.

ADD: We have a runner to run 4 robots, all of them are triggered by creating new files. 3 trigger files are located in server A and the left 1 trigger is located in another server B. During the error, all triggers in server A didnt work and no record left in evenwatcher. But the trigger in another server worked well with correct record in eventwatcher.

We have checked server setting, no error happend and no firewall settings which might cut the connection.