Using Classic Outlook on Windows for personal email, calendar, and contact management
I was having this problem, but thank God Almighty, who made me check the filters.
I realise the sort at the bottom was set to sort by From instead of Date.
Selecting sort by Date resolved the issue, and all current emails that were not showing became visible a moment ago.
Please tick also sort by Newest on top if it's not already selected. I have provided an image below with instructions to make it easy to resolve the issue.
I did this hoping that it would help someone who is experiencing the same problem. It might not work for everyone, but trying doesn't hurt.
God bless you all, and know that Jesus Christ loves you. Jehovah Almighty God loves you too, and be blessed.