Sender ID:
Monaco Telecom (21201) is filtering on Shortcode Sender IDs. We suggest you use International format Numeric Sender to bypass Monaco Telecom filtering.
Content:
There are no additional content restrictions beyond those in our Acceptable Use Policy
Other features/restrictions of note:
Delivery Receipts:
Handset delivery receipts are supported.
Links:
Global SMS Features Overview (Outbound only)
Global SMS Numbers Features Overview