This came up for me and some others recently when trying to get the VM up on Win10 20H2 (which may or may not be relevant). After the 1st Vagrant up, it works fine but once the machine is halted and restarted it will no longer connect to the /vagrant folder and goes into a timeout loop. The work around is to "do-release-upgrade" on the first successful login which updates to Ubuntu 16.04.7 LTS, there is probably a much less time consuming fix but thats a bit above my pay grade.
This came up for me and some others recently when trying to get the VM up on Win10 20H2 (which may or may not be relevant). After the 1st Vagrant up, it works fine but once the machine is halted and restarted it will no longer connect to the /vagrant folder and goes into a timeout loop. The work around is to "do-release-upgrade" on the first successful login which updates to Ubuntu 16.04.7 LTS, there is probably a much less time consuming fix but thats a bit above my pay grade.