Unable to send a message to a contact from Zoho CRM

Unable to send a message to a contact from Zoho CRM

From menu Contacts I choose a contact, on the right vertical menu i have five different choices:
Add a potential, 
Add an activity 
Add an event 
Add a call 
Send a message. 

All af them works exept "Send a message".
If i click on it I don't get nothing, no error message no freeze no nothing!
Any help will be appreciated.