Printer issues NT/2000

We have an NT 4.0 and 2000 enviroment on a newly installed VLAN. Some of the printers on NT4.0 print servers drop connectivity, i.e. STATUS NOT AVAILABLE. I then can go into the printer properties click on PORT and the CONFIGURE PORT, cancel, cancel and the jobs start printing.
I thought maybe my moving them to WIndows 2000 printer server this might resolve this issue. NOT….Any suggestions….It happens on Kyocera 1700 and HP 4 printers…But not all of them…