All Messges to FTP server are stuck

Hi

All messages which are going to FTP server are stuck. Till yesterday it was working fine. Now I could see all the messages which are going to three different FTP server are in "TO BE DELIVERED" state and remaing messges which are going to R/3, webservice etc are working fine.

These messages are in this state from last 6 hours.. I could not see any error in SXMB_MONI or Runtime workbench. Cache is also working fine.

Could you please help me in this.

Regards

Sowmya