diff --git a/youtube/accounts.py b/youtube/accounts.py
index 4108269..bde9852 100644
--- a/youtube/accounts.py
+++ b/youtube/accounts.py
@@ -64,10 +64,10 @@ def add_account(env, start_response):
         use_tor = False
 
     if _add_account(parameters['username'][0], parameters['password'][0], save_account, use_tor ):
-        start_response('200 OK',  () )
+        start_response('200 OK',  [('Content-type', 'text/plain'),] )
         return b'Account successfully added'
     else:
-        start_response('200 OK',  () )
+        start_response('200 OK',  [('Content-type', 'text/plain'),] )
         return b'Failed to add account'
 
 def get_account_login_page(env, start_response):
diff --git a/youtube/channel.py b/youtube/channel.py
index 6acb371..1ec5635 100644
--- a/youtube/channel.py
+++ b/youtube/channel.py
@@ -402,7 +402,7 @@ def get_channel_page(env, start_response):
 
         result = channel_search_page(polymer_json, query, page_number, number_of_videos, env['QUERY_STRING'])
     else:
-        start_response('404 Not Found', ())
+        start_response('404 Not Found', [('Content-type', 'text/plain'),])
         return b'Unknown channel tab: ' + tab.encode('utf-8')
 
     start_response('200 OK', [('Content-type','text/html'),])
@@ -423,7 +423,7 @@ def get_channel_page_general_url(env, start_response):
         page = 'videos'
         base_url = 'https://www.youtube.com/' + '/'.join(path_parts)
     else:
-        start_response('404 Not Found', ())
+        start_response('404 Not Found', [('Content-type', 'text/plain'),])
         return b'Invalid channel url'
 
     if page == 'videos':
@@ -446,7 +446,7 @@ def get_channel_page_general_url(env, start_response):
         polymer_json = json.loads(polymer_json)
         return channel_search_page('''
     else:
-        start_response('404 Not Found', ())
+        start_response('404 Not Found', [('Content-type', 'text/plain'),])
         return b'Unknown channel page: ' + page.encode('utf-8')
 
     start_response('200 OK', [('Content-type','text/html'),])
diff --git a/youtube/local_playlist.py b/youtube/local_playlist.py
index bfca48f..0375040 100644
--- a/youtube/local_playlist.py
+++ b/youtube/local_playlist.py
@@ -155,7 +155,7 @@ def path_edit_playlist(env, start_response):
         return b''
 
     else:
-        start_response('400 Bad Request', ())
+        start_response('400 Bad Request', [('Content-type', 'text/plain'),])
         return b'400 Bad Request'
 
 def edit_playlist(env, start_response):
@@ -165,5 +165,5 @@ def edit_playlist(env, start_response):
         add_to_playlist(parameters['playlist_name'][0], parameters['video_info_list'])
         start_response('204 No Content', ())
     else:
-        start_response('400 Bad Request', ())
+        start_response('400 Bad Request', [('Content-type', 'text/plain'),])
         return b'400 Bad Request'
diff --git a/youtube/watch.py b/youtube/watch.py
index 9e3a1c2..04a5b5d 100644
--- a/youtube/watch.py
+++ b/youtube/watch.py
@@ -231,7 +231,7 @@ music_list_table_row = Template('''<tr>
 def get_watch_page(env, start_response):
         video_id = env['parameters']['v'][0]
         if len(video_id) < 11:
-            start_response('404 Not Found', ())
+            start_response('404 Not Found', [('Content-type', 'text/plain'),])
             return b'Incomplete video id (too short): ' + video_id.encode('ascii')
 
         start_response('200 OK', [('Content-type','text/html'),])
diff --git a/youtube/youtube.py b/youtube/youtube.py
index 988e09a..240e785 100644
--- a/youtube/youtube.py
+++ b/youtube/youtube.py
@@ -75,11 +75,11 @@ def youtube(env, start_response):
                 return f.read().replace(b'$port_number', str(settings.port_number).encode())
 
         elif path == "/comment_delete_success":
-            start_response('200 OK',  () )
+            start_response('200 OK', [('Content-type', 'text/plain'),] )
             return b'Successfully deleted comment'
 
         elif path == "/comment_delete_fail":
-            start_response('200 OK',  () )
+            start_response('200 OK',  [('Content-type', 'text/plain'),] )
             return b'Failed to deleted comment'
 
         else:
@@ -97,9 +97,9 @@ def youtube(env, start_response):
         else:
             return handler(env, start_response)
 
-        start_response('404 Not Found', ())
+        start_response('404 Not Found', [('Content-type', 'text/plain'),])
         return b'404 Not Found'
 
     else:
-        start_response('501 Not Implemented', ())
+        start_response('501 Not Implemented', [('Content-type', 'text/plain'),])
         return b'501 Not Implemented'