Sometimes Fusion can't connect to internet

[Rumboogy]

Sometimes Fusion can't connect to internet and gives an error message:
  Could not connect 'Ethernet0' to virtual network '/dev/vmnet8'.
  More information can be found in the vmware.log file.
  Virtual device 'Ethernet0' will start disconnected.

This happens when I start Fusion and boot Windows VM while connected to a certain network. If I start Fusion and boot Windows VM while connected to a different network I don't get this issue. Once the Windows VM is up and running I can connect to any network without any issue. So the problem only occurs when the VM is starting up and is connected to one specific network. 

I am running Fusion on a different Mac and I don't have this problem.  I have even copied the VM guest from the problem Mac to the non-problem Mac and I don't have the issue.  So it seems like this issue is related to the installation of VMware Fusion on one particular Mac. 

The problem first manifested it self about a year ago when I upgrade the macOS from Catalina to Big Sur.

[ColoradoMarmot]

If you're using bridged, try nat.  Some networks won't allow multiple IP address for a single MAC address.

[Rumboogy]

I have selected the "Share with my Mac" option under Network Adapter which says it is NAT.

[ColoradoMarmot]

Anything like little snitch or other firewalls installed on that mac?

That's really odd...

[Rumboogy]

Yes, Little Snitch.

[Rumboogy]

This problem started when I changed my ISP to ATT (I had previously said that it started when I updated macOS but that was wrong).  The strange thing about this issue is that it occurs on only one of two Macs that I have running Fusion.

[ColoradoMarmot]

Are you using AT&T provided equipment?  Some networks are configured to only issue one IP address to a given physical MAC address.

Regardless, I'd definitely look into getting your own cable modem and router.  It's 1) cheaper, 2) a lot more private and secure, and 3) gives you control over your own network config.

[Rumboogy]

Yes you are correct, I have ATT's Fiber service.  Unfortunately I have to use their "residential gateway" which is a piece of crap.  I had so many problems with the ATT gateway that I connected an ASUS router to it in pass-through mode and I only connect to that device (the ASUS router).  This is not a cable service so I don't have the choice to buy my own modem. 

The strange thing is that the problem only occurs on one Mac and not the other Mac.  So there is something specific to the setup of the problem Mac that is causing this.  So I am sure that there is someway to fix this.