Microsoft Graph API Create Group Fails

Using Microsoft Graph API 1.0 on an Azure AD B2C directory, I'm running into the following problem when creating groups.

I'm able to create a group with the following code

payload = {
    "description": group_name,
    "displayName": group_name,
    "groupTypes": [
        "Unified"
    ],
    "mailEnabled": False,
    "mailNickname": azure_user_id,
    "securityEnabled": True,
    "owners@odata.bind": [Config.GRAPH_API_BASE + "users/" + azure_user_id],
    "members@odata.bind": [Config.GRAPH_API_BASE + "users/" + azure_user_id]
}

graph_api_post(Config.GRAPH_API_BASE + "groups", payload)

This creates a group with the specified name with a single owner who is also a member of the group.

However, having created one group this way, if I try to create a second group, with the same user, in the same manner, but with a different name, the API fails. In other words I can create:

Name: Group 1

Owner: "Me"

Members: "Me"

But when I try to create a second group as below, the API throws a 500 error.

Name: Group 2

Owner: "Me"

Members: "Me"

Using the Azure Portal, I'm able to create the second group, so this doesn't appear to be a limitation of groups in general, just a limitation / bug of the Graph API.

Is this limitation documented somewhere? Is there a workaround?

Based on Properties of Group, mailNickname is unique in the organization.

So you should specify a different value for mailNickname. Otherwise you will get 500 error.