Two possible reasons for this would be if

(A) The extensions are disabled (only enabled extensions are listed on the Extension button drop-down)

(B) You are using a private window but the extensions are not allowed to run in private windows. This article describes how to check on that: Extensions in Private Browsing.

Otherwise, hmm, something may have gone very wrong.

You can check the Browser Console for possible messages about those extensions.

• https://firefox-source-docs.mozilla.org/devtools-user/browser_console/

You can check for problems with the extensions registry files in the profile folder.

Try to reset the extensions registry and rename extensions.json (extensionsOLD.json) and rename/remove compatibility.ini in the Firefox profile folder with Firefox closed.

• https://support.mozilla.org/en-US/kb/Profiles

New files will be created when required.

See "corrupt extension files":

• https://support.mozilla.org/en-US/kb/unable-install-add-ons-extensions-or-themes

You can check for possible updates in case of issues.

• click the cogwheel (left of the Search bar) on the about:addons page to "Check for updates"

You can use the button on the "Help -> More Troubleshooting Information" (about:support) page to go to the current Firefox profile folder or use the about:profiles page (Root directory).

• Help -> More Troubleshooting Information -> Profile Folder/Directory:
  Windows: Open Folder; Linux: Open Directory; Mac: Show in Finder
• https://support.mozilla.org/en-US/kb/profiles-where-firefox-stores-user-data

jscher2000 Thanks for your reply. Extensions are enabled and not using private browsing. Looks like Otherwise.......

Thanks guys for your help. Problem solved by refreshing Firefox.