Personalised Focus not receiving Telegram notifications on iPhone

i have created a new focus by only allowing 1 person’s notifications to be received. at first it was working via all my apps, however, it stopped working. for example, i was able to get his notifications from telegram in the beginning but now i am unable to do so. i have restarted my phone a few times and deleted to create the new focus again. please list down some solutions on how to fix this, thanks!

[Re-Titled by Moderator]