I try to create a custom datetime property via the API, but somehow the response says that my property group name contactinformation is incorrect. I got that value from the docs.
In your production account ending in 6458, contactinformation is a valid groupName. For example, if you query this endpoint for contact property firstname, you will see groupName: "contactinformation" in the response.
Just to confirm, can you verify that you are making requests to account 6458 and not your developer account ending in 8261? Developer accounts do not have contact property groups.
Please try to use contact_information in place of contactinformation in contact group name. Else you can first create a seperate new contact property group and then can use that group internal name under property create request.
In your production account ending in 6458, contactinformation is a valid groupName. For example, if you query this endpoint for contact property firstname, you will see groupName: "contactinformation" in the response.
Just to confirm, can you verify that you are making requests to account 6458 and not your developer account ending in 8261? Developer accounts do not have contact property groups.