Was your management host - from which you're initially managing your Switch - moved to a VLAN Id 2 untaggeed port (from being connected to a VLAN Id 1 untagged port) or, at least, moved on a port that is untagged on VLAN Id 1 and tagged on VLAN Id 2 so it can reach VLAN Id 2 Management IP just after the change? or am I missing anything else?
Edit: WAN Routing- no WAN Routing issue here - is clearly wrong as HPE Community's thread category...better to ask moderator to move this thread into the correct category at Web and Unmanaged here.