diff --git a/addons/sms/wizard/sms_composer.py b/addons/sms/wizard/sms_composer.py
index 2f24cbf6c3a..ce7d2c1b42c 100644
--- a/addons/sms/wizard/sms_composer.py
+++ b/addons/sms/wizard/sms_composer.py
@@ -35,6 +35,7 @@ class SendSMS(models.TransientModel):
         ('mass', 'Send SMS in batch')], string='Composition Mode',
         compute='_compute_composition_mode', precompute=True, readonly=False, required=True, store=True)
     res_model = fields.Char('Document Model Name')
+    res_model_description = fields.Char('Document Model Description', compute='_compute_res_model_description')
     res_id = fields.Integer('Document ID')
     res_ids = fields.Char('Document IDs')
     res_ids_count = fields.Integer(
@@ -76,6 +77,12 @@ class SendSMS(models.TransientModel):
                 else:
                     composer.composition_mode = 'comment'
 
+    @api.depends('res_model')
+    def _compute_res_model_description(self):
+        self.res_model_description = False
+        for composer in self.filtered('res_model'):
+            composer.res_model_description = self.env['ir.model']._get(composer.res_model).display_name
+
     @api.depends('res_model', 'res_id', 'res_ids')
     def _compute_res_ids_count(self):
         for composer in self:
diff --git a/addons/sms/wizard/sms_composer_views.xml b/addons/sms/wizard/sms_composer_views.xml
index c0df1af4a2f..34bdfce181a 100644
--- a/addons/sms/wizard/sms_composer_views.xml
+++ b/addons/sms/wizard/sms_composer_views.xml
@@ -5,6 +5,25 @@
         <field name="model">sms.composer</field>
         <field name="arch" type="xml">
             <form string="Send an SMS">
+                <!-- Single mode information (invalid number) -->
+                <div colspan="2" class="alert alert-danger text-center mb-0" role="alert"
+                    attrs="{'invisible': ['|', '|', ('res_model_description', '=', False), ('comment_single_recipient', '=', False), ('recipient_single_valid', '=', True)]}">
+                    <p class="my-0">
+                        <strong>Invalid number:</strong>
+                        <span> make sure to set a country on the </span>
+                        <span><field name="res_model_description"/></span>
+                        <span> or to specify the country code.</span>
+                    </p>
+                </div>
+
+                <!-- Mass mode information (res_ids versus active domain) -->
+                <div colspan="2" class="alert alert-info text-center mb-0" role="alert"
+                        attrs="{'invisible': ['|', ('comment_single_recipient', '=', True), ('recipient_invalid_count', '=', 0)]}">
+                    <p class="my-0">
+                        <field class="oe_inline font-weight-bold" name="recipient_invalid_count"/> out of
+                        <field class="oe_inline font-weight-bold" name="res_ids_count"/> recipients have an invalid phone number and will not receive this text message.
+                    </p>
+                </div>
                 <sheet>
                     <group>
                         <field name="composition_mode" invisible="1"/>
@@ -19,21 +38,6 @@
                         <field name="numbers" invisible="1"/>
                         <field name="sanitized_numbers" invisible="1"/>
 
-                        <!-- Single mode information (invalid number) -->
-                        <div colspan="2" class="alert alert-danger text-center mb-3" role="alert"
-                            attrs="{'invisible': ['|', ('comment_single_recipient', '=', False), ('recipient_single_valid', '=', True)]}">
-                            <p class="my-0">Invalid phone number</p>
-                        </div>
-
-                        <!-- Mass mode information (res_ids versus active domain) -->
-                        <div colspan="2" class="alert alert-info text-center mb-3" role="alert"
-                                attrs="{'invisible': ['|', ('comment_single_recipient', '=', True), ('recipient_invalid_count', '=', 0)]}">
-                            <p class="my-0">
-                                <field class="oe_inline font-weight-bold" name="recipient_invalid_count"/> out of
-                                <field class="oe_inline font-weight-bold" name="res_ids_count"/> recipients have an invalid phone number and will not receive this text message.
-                            </p>
-                        </div>
-
                         <label for="recipient_single_description" string="Recipient"
                             class="font-weight-bold"
                             attrs="{'invisible': [('comment_single_recipient', '=', False)]}"/>