When creating a Site Collection with the “Group” template in Office 365 in Sharegate, you receive this error message:
Unable to create the Office 365 group as there is already a group with the same alias.
Every Office 365 group has an alias which is used for the email of the group (i.e. firstname.lastname@example.org). When creating a Site Collection with the “Group” template in Office 365, Sharegate first must create an Office 365 group.
The alias of the created Office 365 group will be based on the URL chosen for the created Site Collection. For example if the URL chosen is ‘sites/sales” the Office 365 group alias will be “sales”.
If you get the error that there is already a group with the same alias, it means that in your admin center in your destination, there exists an Office 365 group with the chosen alias.
1 - Select another URL for your destination Site Collection in order to have an Office 365 group with an alias that is not already used in your destination admin center.
2 – If the Office 365 group at destination with the same alias is not used, you may delete it and restart the migration.
3 - If the Office 365 group at destination does not have an associated Site Collection, you may try to reprovision it in your web browser by navigating to your Office 365 group and selecting Files. Then wait for the Site Collection to be fully created and you will then be able to merge your source Site into the existing Site Collection at the destination.