MMS Limitations:

•  The maximum size for attachments is 3MB.
• It is recommended that only one attachment be sent at a time to avoid exceeding the carrier's size limit.
• Microsoft Teams Connector will support whatever file types your carrier supports. 
  • To confirm supported file types, refer to your carrier's documentation.
• The carrier may change file names in transit. Do not be alarmed if the file name appears as a hash when it reaches the recipient.
• MMS attachments will be retained on the Microsoft Teams Connector server for one month.
• Twilio sometimes sends attachments as hyperlinks to an SMS message.