Random SMB Connection Failure (3 mounts)

Hi Everybody

I have a server (Server1) which runs autofs to create my mounts to 3 other servers (NetServ1,NetServ2,NetServ3) which have shared folders on them. When booting up Server1 autofs works fine and creates my mount points in the folder /mnt.....from there on Server 1 access these mount points to the 3 other servers as it wishes, it fetches files and does reports...for some reason after a while of running server1 i just get a "SMB Connection Failure" from any one of those mount points, its like my external servers just decide to refuse the connection to server1 all of a sudden, or the mount point just stops functioning

Can anyone please assist me

oh i forgot to mention that as soon as one of the three servers refuses server1 from connecting autofs unmounts the connection and re mounts but still gets refused