{"id":49811,"date":"2026-05-22T12:00:26","date_gmt":"2026-05-22T12:00:26","guid":{"rendered":"https:\/\/vger.datos.co.uk\/Clientknowledgebase\/?p=49811"},"modified":"2026-05-22T12:00:39","modified_gmt":"2026-05-22T12:00:39","slug":"error-503-when-accessing-web-app","status":"publish","type":"post","link":"https:\/\/vger.datos.co.uk\/Clientknowledgebase\/?p=49811","title":{"rendered":"Error 503 when accessing Web App"},"content":{"rendered":"\n

If you get error 503 when loading the Web App, this can indicate that there is a problem with IIS rather than with the Web App configuration.<\/p>\n\n\n\n

This is usually accompanied by the ‘Application Pool’ processes crashing. This can be checked by:<\/p>\n\n\n\n

    \n
  1. Loading IIS.<\/li>\n\n\n\n
  2. Expanding the main server node.<\/li>\n\n\n\n
  3. Double Clicking on ‘Application Pools’.<\/li>\n\n\n\n
  4. If any of the application pools have a stopped symbol (small black square) on their icon, they have probably crashed.<\/li>\n<\/ol>\n\n\n\n

    The root cause of the 503 error is usually that there are links to old Dataflex Web App components that have been uninstalled or moved.<\/p>\n\n\n\n

    To check the Dataflex components, the following needs to be checked on the main server node, each website note, and each folder node.<\/p>\n\n\n\n

    Checking the Installed Native Modules At the Server level<\/strong><\/p>\n\n\n\n

      \n
    1. Select the main server node in the ‘Connections’ treeview on the left hand panel<\/li>\n\n\n\n
    2. From the main ‘Features View’, double click on ‘Modules’<\/li>\n\n\n\n
    3. Click on ‘Configure Native Modules’ in the panel on the right hand side<\/li>\n\n\n\n
    4. Check for any modules for invalid DataFlex components. The location of the component can be checked with the ‘Edit’ button (server node only).<\/li>\n\n\n\n
    5. Click on them, then click on the ‘Remove’ button (this only shows up on the server level page)<\/li>\n<\/ol>\n\n\n\n

      Checking the Installed Native Modules at the folder level<\/strong><\/p>\n\n\n\n

        \n
      1. Select the folder in the ‘Connections’ treeview.<\/li>\n\n\n\n
      2. From the main ‘Features View’, double click on ‘Modules’<\/li>\n\n\n\n
      3. Check for any modules pointing to invalid Dataflex Components. <\/li>\n\n\n\n
      4. Click on them, and then click on remove in the panel on the right<\/li>\n<\/ol>\n\n\n\n

        Checking the Handler Mappings<\/strong><\/p>\n\n\n\n

          \n
        1. Select the folder in the ‘Connections’ treeview.<\/li>\n\n\n\n
        2. From the main ‘Featues View’, double click on ‘Handler Mappings’.<\/li>\n\n\n\n
        3. Look for any mappings with ‘Path’ as ‘*.wso’ that point to invalid Dataflex components.<\/li>\n\n\n\n
        4. Select them and click on ‘Remove’ on the right hand side panel.<\/li>\n<\/ol>\n\n\n\n

          Stop and restart the IIS service by right clicking on the server node and selecting stop, then start.<\/p>\n","protected":false},"excerpt":{"rendered":"

          If you get error 503 when loading the Web App, this can indicate that there is a problem with IIS rather than with the Web App configuration. This is usually accompanied by the ‘Application Pool’ processes crashing. This can be checked by: The root cause of the 503 error is usually that there are links […]<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[8,22],"tags":[552,672],"class_list":["post-49811","post","type-post","status-publish","format-standard","hentry","category-troubleshootingguides","category-troubleshootingseasononlineroad","tag-error","tag-672"],"_links":{"self":[{"href":"https:\/\/vger.datos.co.uk\/Clientknowledgebase\/index.php?rest_route=\/wp\/v2\/posts\/49811","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/vger.datos.co.uk\/Clientknowledgebase\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/vger.datos.co.uk\/Clientknowledgebase\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/vger.datos.co.uk\/Clientknowledgebase\/index.php?rest_route=\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/vger.datos.co.uk\/Clientknowledgebase\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=49811"}],"version-history":[{"count":2,"href":"https:\/\/vger.datos.co.uk\/Clientknowledgebase\/index.php?rest_route=\/wp\/v2\/posts\/49811\/revisions"}],"predecessor-version":[{"id":49814,"href":"https:\/\/vger.datos.co.uk\/Clientknowledgebase\/index.php?rest_route=\/wp\/v2\/posts\/49811\/revisions\/49814"}],"wp:attachment":[{"href":"https:\/\/vger.datos.co.uk\/Clientknowledgebase\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=49811"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/vger.datos.co.uk\/Clientknowledgebase\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=49811"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/vger.datos.co.uk\/Clientknowledgebase\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=49811"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}