Core issue
This happens when configuring the switch as VTP client mode without deleting the vlan.dat file. When the switch is rebooted, the switch shows up as a VTP server and not a client.
Resolution
Follow these steps in order to resolve this issue:
Delete the vlan.dat file.
Configure the switch in VTP client mode using the command vtp mode client.
Issue the copy running-config startup-config command if you are configuring from global configuration mode. However, in a VLAN database, you need to enter exit in order to save these settings.
Do not delete the vlan.dat file at this point. If you do, it goes back to the default mode (for example, Sever mode).
Reload the switch and verify the VTP mode using the show vtp status command.
For more information, refer to Understanding and Configuring VLAN Trunk Protocol (VTP).
