diff --git a/addons/mail/static/src/xml/composer.xml b/addons/mail/static/src/xml/composer.xml
index bb9321a749d..d09b6bc4f22 100644
--- a/addons/mail/static/src/xml/composer.xml
+++ b/addons/mail/static/src/xml/composer.xml
@@ -79,8 +79,15 @@
     </t>
 
     <t t-name="FieldMany2ManyTagsEmail" t-extend="FieldMany2ManyTag">
-        <t t-jquery=".o_badge_text" t-operation="replace">
-            <span class="o_badge_text" t-attf-title="#{el.email}"><t t-esc="el.display_name"/></span>
+        <t t-jquery="span[t-attf-class*=badge]" t-operation="replace">
+            <t t-set="email_error" t-value="''"/>
+            <t t-if="el.email.indexOf('@') &lt; 0">
+                <t t-set="email_error" t-value="'o_tag_error'"/>
+            </t>
+            <span t-attf-class="badge dropdown o_tag_color_0 #{email_error}" t-att-data-color="color" t-att-data-index="el_index" t-att-data-id="el.id">
+                <span class="o_badge_text" t-attf-title="#{el.email}"><t t-esc="el.display_name"/></span>
+                <span t-if="!readonly" class="fa fa-times o_delete"/>
+            </span>
         </t>
     </t>
 </templates>
diff --git a/addons/web/static/src/scss/fields.scss b/addons/web/static/src/scss/fields.scss
index 0fd69037b0b..2a35c33005a 100644
--- a/addons/web/static/src/scss/fields.scss
+++ b/addons/web/static/src/scss/fields.scss
@@ -173,6 +173,12 @@
                     }
                 }
             }
+        }        
+        > .o_tag_error{ 
+            box-shadow: inset 0 0 0 2px #FF0000;
+            > .o_delete {
+                color: #FF0000;
+            }
         }
     }