Some users reported that after the update to Uyuni 2023.03, the notification page was completely blank  
If you are affected, you will see notifications on the bell icon at the WebUI, and you will still get e-mail notifications. But if you go to the notifications page, it will render completely blank, with no content at all or errors.
Although this should only affect Uyuni users with SCC credentials added to the Setup Wizard and with SCC subscriptions expiring, a previous bug  can cause this same problem even for some users without SCC subscriptions if they got such notifications but never removed them.
A patch for Uyuni 2022.03 is now available, in case you are affected, so you do not need to wait for the next Uyuni release.
You can apply the patch at the Uyuni Server by following the instructions at: https://www.uyuni-project.org/pages/patches.html
If you are still on 2023.01 or earlier, update first to 2023.03 normally (make sure you read the release notes, as special steps may be required if you are not on 2023.03 already), and then apply the patch as explained above.
 https://firstname.lastname@example.org/messa...  https://github.com/uyuni-project/uyuni/issues/6729  https://github.com/uyuni-project/uyuni/issues/6375