Many Outlook users are getting the ‘Unlicensed Product’ error at every initiation even when they pay for the subscription. The issue is not operative System exclusive as it comes even with office 365 and with office 2016 too.
You might be the one dealing with a network discontinuity. The easiest troubleshoot can be managed by running the Activation troubleshooter that is compatible with office 365 or the one you use.
To resolve the issue you can try eliminating any element manually that gets recommended, Also you should try to do some adjustments and should manually remove every element that involves office activation via CMD or a Registry Editor and Credentials Manager in case they could help you out in dealing and resolving the issue.
If you have updated the recent subscription and have tried out all the possible troubleshooting, look for an IT professional to help you out. You can also check out the Microsoft help Center in case the issue is unique to your system.