Inbound mean Imap in WF Mailer of EBS.
So when you set it to 0, you actually disable Inbound / IMAP.
When you set it to 1 for instance, then you enable the IMAP side.
In your conf, you have an IMAP connection problem with the IMAP Server that you have (given MYSERVER in your example screenshot)
So probably, your apps node can not reach the IMAP Server.. That may be caused by firewall or MYSERVER may not even be an IMAP server and etc..
Check with your system admin.
Additional info: Default port of IMAP is 143. (IMAPS port is 993)