I have implemented mapserver in Ubuntu 14.04 with postgresql 9.3, postgis and imposm using GitHub tutorial. After completing the tutorial all map services display pink tiles not map info. i was not encounter with any issues during the tutorial run. any reason to this?
Following screenshots for your reference.

When I check network I saw some errors as follows it shows as bad gate way and internal server error

here's my basemap makefile and mapcache.xml file
basemap/makefile
UNAME := $(shell uname)
ifeq ($(UNAME), Darwin)
SED=sed -i ""
else
SED=sed -i
endif
CPP=gcc -E -x c
#if the preprocessor fails for some reason, try replacing this with "cpp" on linux, or "cpp-4.2" on darwin (not available starting with mountain lion)
OSM_PREFIX=osm_new_
OSM_NAME_COLUMN=name
OSM_SRID=4326
OSM_UNITS=dd
OSM_EXTENT=-180 -90 180 90
OSM_SRID=3857
OSM_UNITS=meters
OSM_DB_CONNECTION=host=localhost dbname=osm user=osm password=osm port=5432
OSM_EXTENT=-20000000 -20000000 20000000 20000000
OSM_WMS_SRS=EPSG:900913 EPSG:4326 EPSG:3857 EPSG:2154 EPSG:310642901 EPSG:4171 EPSG:310024802 EPSG:310915814 EPSG:310486805 EPSG:310702807 EPSG:310700806 EPSG:310547809 EPSG:310706808 EPSG:310642810 EPSG:310642801 EPSG:310642812 EPSG:310032811 EPSG:310642813 EPSG:2986
DEBUG=1
LAYERDEBUG=1
STYLE=google
#can also use google or bing
mapcache-osm.xml
<?xml version="1.0" encoding="UTF-8"?>
<!-- see the accompanying https://github.com/mapserver/mapcache/blob/master/mapcache.xml.sample for a fully commented configuration file -->
<mapcache>
<cache name="disk" type="disk">
<base>/home/sithila/osm-demo/mapcache/cache</base> <!-- Change Path here -->
<symlink_blank/>
</cache>
<source name="osm" type="wms">
<getmap>
<params>
<FORMAT>image/png</FORMAT>
<LAYERS>default</LAYERS>
<MAP>/home/sithila/osm-demo/basemaps/osm-google.map</MAP> <!-- Change Path here -->
</params>
</getmap>
<http>
<url>http://localhost/cgi-bin/mapserv?</url> <!-- Change server here -->
</http>
</source>
<tileset name="osm">
<metadata>
<title>OSM MapServer served map</title>
<abstract>see https://github.com/mapserver/mapserver/wiki/RenderingOsmDataUbuntuv2</abstract>
</metadata>
<source>osm</source>
<cache>disk</cache>
<grid>WGS84</grid>
<grid>g</grid>
<format>PNG</format>
<metatile>5 5</metatile>
<metabuffer>10</metabuffer>
<expires>10000</expires>
<auto_expire>86400</auto_expire>
</tileset>
<default_format>JPEG</default_format>
<service type="wms" enabled="true">
<full_wms>assemble</full_wms>
<resample_mode>bilinear</resample_mode>
<format>JPEG</format>
<maxsize>4096</maxsize>
</service>
<service type="wmts" enabled="true"/>
<service type="tms" enabled="true"/>
<service type="kml" enabled="true"/>
<service type="gmaps" enabled="true"/>
<service type="ve" enabled="true"/>
<service type="demo" enabled="true"/>
<errors>report</errors>
<lock_dir>/tmp</lock_dir>
</mapcache>
In my further troubleshooting i have execute curl command with a url of a pink tile and received as follows.
<?xml version='1.0' encoding="UTF-8" standalone="no" ?>
<!DOCTYPE ServiceExceptionReport SYSTEM "http://schemas.opengis.net/wms/1.1.1/exception_1_1_1.dtd">
<ServiceExceptionReport version="1.1.1">
<ServiceException>
<![CDATA[
wms request for tileset osm returned an unsupported format:
<!DOCTYPE HTML PUBLIC "-//IETF//DTD HTML 2.0//EN">
<html><head>
<title>404 Not Found</title>
</head><body>
<h1>Not Found</h1>
<p>The requested URL /cgi-bin/mapserv was not found on this server.</p>
<hr>
<address>Apache/2.4.7 (Ubuntu) Server at localhost Port 80</address>
</body></html>
]]>
</ServiceException>