strange squid problem

[Paal Marker]

In this network there are a mix of ms-windows w2k and nt4,  and rh8 
workstations,  server rh9  running squid 2.5  When squid is running, all 
of the windows workstations get only a blank page after logging in to 
the microsoft hotmail service. By logging in from redhat workstations 
hotmail works as normal.  We have no other problems in other sites,

Emptying the squid cache does not help,  but when the squid service is 
totally stopped we can log into hotmail also on the ms-windows 
workstations.  No doubt that squid is the problem here.

Have anybody seen this before?