App No Longer Available. The developer has removed this app from the App Store

If you check that app via App Store Connect, what is the status?

Can new users purchase/install v 1.1

Have you tested undating on your own device?

This happens when the User frequently changes their Region associated to their Apple ID. Your app might be available for only United States and India, it will throw a message that the app is no longer available.
Ideally Apple refreshes the Appstore app in phone when the region is changed, but it clearly didn’t happen.
To solve this customer will need to set their Apple ID Region to United States using these steps

Home Screen > Settings
Tap on Apple ID
Tap on Media & Purchases (Authenticate if needed)
Select Country/Region
Tap on Change Country or Region
Select US and enter complete detail

Moving now to AppStore will probably fix this issue.

Why is „DManager Browser & Documents“ gone. It was my favourite free offline music player. I had a iphone SE and had the app just fine. But when i changed to an iphone 11 and transferred everything from my SE to my 11 DManager Browser & Documents can’t be downloaded once again because „The app is no longer available in the app store.“ why is that?!

Thank you ioskunal. I followed the steps you recommended but after I click on country/region, a message pops up saying I have 1 or more apple subscriptions which must be cancelled before I can change country region. Is there anyway around this?

I purchased the HooToo Flash Drive 3 in 1 External Drive, USB 3.1 Memory Backup Stick 256GB a few months ago and just recently wanted to transfer pictures/files from my iPhone to my computer to free up some memory. When I went to search for the U-hub app in the App Store it couldn’t be found. Anyone else having this problem?

I was able to resolve by delete and install again.