What does the error about a maximum number of groups mean?

There is a maximum number of groups allowed within each account in order to maintain a fast and efficient system for all users.

If you receive the following error message:

Maximum number of groups reached. You must delete at least one group before adding a new group.

You will need to delete at least one group in your account before you can add any new groups.

Note when you delete a group, the contacts will not be deleted from the account. Also if at any time you need to locate the groups and/or contacts that received a particular campaign, that can be done via the campaign reports rather than needing to maintain a group per campaign.

And lastly you can also take an archive record of all groups and contacts currently stored in your account before deleting by exporting via Contacts tab > Print/Export drop down menu. This file will include in column AM the group(s) a particular contact is currently stored in. 

By default the maximum number of groups allowed in an account is 100. (Your company's settings may allow a different number of groups. Contact Support for additional information.)