Group MMS activation failed.

The conversation's Group MMS could not be activated.

• The conversation does not have at least three participants with messaging binding.
• The conversation has got a participant with identity but without projected address.
• The conversation's participants do not make a valid address list for group messaging.

• Check that all the participants have messaging bindings.
• Check that there is at least one participant with user address only.
• Check that there is at least one participant with a proxy address or a projected address.