When I click on the install link (under addons) next to Free Fax, the browser seems to go into an infinite wait and nothing in the admin pages seems to respond.
Should I rather try installing it using the instructions at
Ignore… I left it for ages and it installed 
I now have the free fax installed and licensed, yet under the fax settings for the extensions, I get
“ERROR: No Fax license detected. Fax-related dialplan will NOT be generated! This module has detected that Fax for Asterisk is installed without a license. At least one license is required (it is available for free) and must be installed.”
Under freefax registration it says “Max Registrations”
Rebooted server and it seem to come right.