We have, unfortunately, experienced that some of our customers have Teams automatically installed with newer Microsoft Office 365 updates.
But this update also changes the Office 365 settings to make Teams suppress Skype for Business ny default. This means, among other things, that the Skype meetings booking feature via Outlook disappears.
Fortunately, you can easily change this yourself via your Dashboard in Office 365 (with an administrator login, of course).
Click Teams upgrade under Org-wide settings.
This will allow you to change Coexistence mode for Teams and Skype for Business.
If you want to use Teams in your organisation, we recommend that your use Islands.
If not, simply pick Skype for Business only.
Incidentally...it may also be the case that the coexistence settings for your organisation are locked by Microsoft and cannot be changed by you. In this case, please contact Microsoft.