SAP PI : Communication channel does not pick files up

Hi,

The problem that I have is one of the communication channels stops picking up files suddenly from the FTP server. When I pinged the channel, it shows there are bunch of files that are readable, yet it does not pick them up.

When I restarted the channel, it picks up those files and processes successfully. Can't figure out a possible cause.

The PI version is 7.31, the adapter is the File Adapter, Protocol is FTP.

Appreciate if you could provide some tips / feedback on this.

Thanks,

Theli