In the browser console I see all requests are timing out, for example:
20:49:27.326 1667245767325 addons.update-checker WARN Request for https://versioncheck.addons.mozilla.org/update/VersionCheck.php?reqVersion=2&id={16cbd87c-eb99-4f5c-9825-83cf13ab7ff8}&version=2.1&maxAppVersion=*&status=userEnabled&appID={ec8030f7-c20a-464f-9b0e-13a3a9e97384}&appVersion=107.0&appOS=WINNT&appABI=x86_64-msvc&locale=en-US¤tAppVersion=107.0&updateType=97&compatMode=normal timed out
20:49:27.327 1667245767327 addons.update-checker WARN Request for https://versioncheck.addons.mozilla.org/update/VersionCheck.php?reqVersion=2&id=admin@fastaddons.com_Ctrl_GroupSpeedDial&version=2.6&maxAppVersion=*&status=userEnabled&appID={ec8030f7-c20a-464f-9b0e-13a3a9e97384}&appVersion=107.0&appOS=WINNT&appABI=x86_64-msvc&locale=en-US¤tAppVersion=107.0&updateType=97&compatMode=normal timed out
20:49:27.328 1667245767328 addons.update-checker WARN Request for https://versioncheck.addons.mozilla.org/update/VersionCheck.php?reqVersion=2&id=steam-context-menu@skylark95.com&version=1.2.2&maxAppVersion=*&status=userDisabled&appID={ec8030f7-c20a-464f-9b0e-13a3a9e97384}&appVersion=107.0&appOS=WINNT&appABI=x86_64-msvc&locale=en-US¤tAppVersion=107.0&updateType=97&compatMode=normal timed out
20:49:27.328 1667245767328 addons.update-checker WARN Request for https://versioncheck.addons.mozilla.org/update/VersionCheck.php?reqVersion=2&id={9ea6f004-dfa1-4d80-8cb0-b3f8bfe9004d}&version=1.1.0&maxAppVersion=*&status=userEnabled&appID={ec8030f7-c20a-464f-9b0e-13a3a9e97384}&appVersion=107.0&appOS=WINNT&appABI=x86_64-msvc&locale=en-US¤tAppVersion=107.0&updateType=97&compatMode=normal timed out
20:49:27.328 1667245767328 addons.update-checker WARN Request for https://versioncheck.addons.mozilla.org/update/VersionCheck.php?reqVersion=2&id=admin@fastaddons.com_SendNoteToDevice&version=2.6&maxAppVersion=*&status=userEnabled&appID={ec8030f7-c20a-464f-9b0e-13a3a9e97384}&appVersion=107.0&appOS=WINNT&appABI=x86_64-msvc&locale=en-US¤tAppVersion=107.0&updateType=97&compatMode=normal timed out
20:49:27.328 1667245767328 addons.update-checker WARN Request for https://versioncheck.addons.mozilla.org/update/VersionCheck.php?reqVersion=2&id=display-anchors@robwu.nl&version=1.3&maxAppVersion=*&status=userEnabled&appID={ec8030f7-c20a-464f-9b0e-13a3a9e97384}&appVersion=107.0&appOS=WINNT&appABI=x86_64-msvc&locale=en-US¤tAppVersion=107.0&updateType=97&compatMode=normal timed out
There was a similar issue not long ago, but I can’t remember where, it was some GitHub repo that serves these updates and it had a wrong URL or something…
Edit: reported here.