If the current licenses you hold is Minitab 16/17/18/19, then we would like to inform that it is no longer supported by Minitab.
The activation server for Minitab 16/17/18/19 was decommissioned and is no longer functioning. If you have a working copy of Minitab 16/17/18/19 you can continue using it, but changes in operating systems can modify the original environment in which the software was installed in first place.
Our recommendation is you consider an upgrade to Minitab Version 21, which is offered as an Annual Named-User Subscription which comes complete with maintenance/upgrades, and thus this situation can be avoided in the future.