After replacing layer 3 switch phone manager pro will work after system reboot but after a period of time the VM tab disappears and eventually phone manager will stop working all together. Customer states that this problem did not exist until after a bad layer 3 switch was replaced. The voice and data are on separate VLANS and can communicated between VLANS. Phone manager does work but stops after a period of time beginning with the VM tab disappearing. I have never seen this problem before and I thought maybe someone on this forum may have seen something similar to this. Thanks in advance.