Hashes are used to increase security between your app and the headset. They make sure the same file being hosted on a server matches the one that's been deployed to a headset. If the hashes don't match, the app won't be deployed.
To add a hash to an existing self-hosted app:
Find the SHA-256 hash of the APK you're deploying using a hash application. Copy the hash from the app download or link.
From Oculus for Business Device Manager, click Apps.
Click
next to the app you want to add a hash to, then click Edit.
Paste the copied hash in the Hash section, then click Update.