diff --git a/app/controllers/status_messages_controller.rb b/app/controllers/status_messages_controller.rb
index 88bde91e562fa923a570c0f1f5998a158d3714d2..f830fbf9bdbb5a084429e8da65660e12238d0e7e 100644
--- a/app/controllers/status_messages_controller.rb
+++ b/app/controllers/status_messages_controller.rb
@@ -93,7 +93,8 @@ class StatusMessagesController < ApplicationController
       respond_to do |format|
         format.html { redirect_to :back }
         format.mobile { redirect_to stream_path }
-        format.json { render :text => @status_message.errors.messages[:text].to_sentence, :status => 403 }
+        #there are some errors, so we report the first one to the user
+        format.json { render :text => @status_message.errors.messages.values.first.to_sentence, :status => 403 }
       end
     end
   end
diff --git a/app/models/profile.rb b/app/models/profile.rb
index 622a3e9194aad5f2bf2c5b345bbcdd87b01c0901..8e7e3e4e57ea01cbc5ebea9dbed1e9981f1cf9db 100644
--- a/app/models/profile.rb
+++ b/app/models/profile.rb
@@ -42,6 +42,7 @@ class Profile < ActiveRecord::Base
   belongs_to :person
   before_validation do
     self.tag_string = self.tag_string.split[0..4].join(' ')
+    self.build_tags
   end
 
   before_save do
diff --git a/config/locales/diaspora/en.yml b/config/locales/diaspora/en.yml
index 159a9da4771e57c8403d769d68f23ceaac90e3e0..da5b55a5c76e2a897fcac9827c4fe644f0d860b7 100644
--- a/config/locales/diaspora/en.yml
+++ b/config/locales/diaspora/en.yml
@@ -1253,6 +1253,8 @@ en:
       following: "Following #%{tag}"
       stop_following: "Stop following #%{tag}"
       none: "The empty tag does not exist!"
+    name_too_long: "Please make your tag name fewer than %{count} characters. Right now it is %{current_length} characters"
+    
   tag_followings:
     create:
       success: "Hooray!  You’re now following #%{name}."
diff --git a/lib/diaspora/taggable.rb b/lib/diaspora/taggable.rb
index 0d1396dc3796b1f1463aed72db4af6e3bc0eeb70..3e340df5d84f7df337a2b846d21a90a25191514c 100644
--- a/lib/diaspora/taggable.rb
+++ b/lib/diaspora/taggable.rb
@@ -7,9 +7,20 @@ module Diaspora
     def self.included(model)
       model.class_eval do
         cattr_accessor :field_with_tags
+
+        # validate tag's name maximum length [tag's name should be less than or equal to 255 chars]
+        validate :tag_name_max_length, on: :create
+
+        # tag's name is limited to 255 charchters according to ActsAsTaggableOn gem, so we check the length of the name for each tag
+        def tag_name_max_length
+          self.tag_list.each do |tag|
+            errors[:tags] << I18n.t('tags.name_too_long', :count => 255, :current_length => tag.length) if tag.length > 255
+          end
+        end
+        protected :tag_name_max_length
       end
       model.instance_eval do
-        before_create :build_tags
+        before_validation :build_tags # build tags before validation fixs the too long tag name issue #5737
 
         def extract_tags_from sym
           self.field_with_tags = sym
diff --git a/spec/models/profile_spec.rb b/spec/models/profile_spec.rb
index 2e7379fd144c03f637b37fdaf60490692e7a3396..f62b43ce8818c9b1828d52b00f9e9a5e95bb402f 100644
--- a/spec/models/profile_spec.rb
+++ b/spec/models/profile_spec.rb
@@ -272,6 +272,11 @@ describe Profile, :type => :model do
       @object.save
       expect(@object.tags.count).to eq(5)
     end
+    it 'should require tag name not be more than 255 characters long' do
+      @object.tag_string = "##{'a' * (255+1)}"
+      @object.save
+      expect(@object).not_to be_valid
+    end
     it_should_behave_like 'it is taggable'
   end
 
diff --git a/spec/models/status_message_spec.rb b/spec/models/status_message_spec.rb
index 95c7531dc869cd34757e048a76ae7bd1996c0b3d..605b6ede0349f77a9b558440f6a94ec0d0551d30 100644
--- a/spec/models/status_message_spec.rb
+++ b/spec/models/status_message_spec.rb
@@ -70,6 +70,14 @@ describe StatusMessage, :type => :model do
       expect(guids).to eq([sm1.guid])
     end
   end
+  
+  describe '.before_validation' do
+    it 'calls build_tags' do
+      status = FactoryGirl.build(:status_message)
+      expect(status).to receive(:build_tags)
+      status.save
+    end
+  end
 
   describe '.before_create' do
     it 'calls build_tags' do
@@ -255,6 +263,12 @@ STR
       expect(msg_uc.tags).to match_array(tag_array)
       expect(msg_cp.tags).to match_array(tag_array)
     end
+
+    it 'should require tag name not be more than 255 characters long' do
+      message = "##{'a' * (255+1)}"
+      status_message = FactoryGirl.build(:status_message, :text => message)
+      expect(status_message).not_to be_valid
+    end
   end
 
   describe "XML" do