Hi Billk,
If Malwarebytes for Mac is unable to download updates or activate the license, that means that something is blocking its connection to our servers. That may be an outgoing firewall application, such as Little Snitch or Lulu, or it may be similar functionality that is blocking outgoing connection attempts within some other anti-virus software.
You will need to review any such software and ensure it is not blocking connections that Malwarebytes needs to function properly. See page 5 in the user guide: https://www.malwarebytes.com/pdf/guides/Malwarebytes-For-Mac-User-Guide.pdf