1- Observer : this "Observer" step is mainly dedicated to set the country TLD to filter (ban).
1- The button allow to choose plugin "Observer" in "Security" tab, called "Filtrage contact".
2- Select which contact(s) is to be monitored (most likely all),
3- Set country TLD to filter, separated by ","
2- Action (optional) : send a notification email to administrator, only in case of message attempts from banned TLD.
3- User system message :
If a user from a banned TLD tries to send a message in conventional way through the form, the alert message underneath will be displayed :