campaigns got stuck in between

If they get stuck it means you're using delivery settings that are too high for your server to handle, so lower the delivery server a bit.
@Vpul Shah there is no error in application log.

@twisted1919, i am using 8 gb ram server, only 5-6 campaigns are in process. Installation is also fresh, no old data load, nothing else.
then why campaigns got stuck. I checked server now, it is sending campaigns and stop automatically, then start sending again after 1-2 hours automatically.

this is weird issue. i scheduled new campaign in another customer account with different smtp, it is got stuck in pending-sending status.

can you please help me out?