If you want to block RPC over HTTPS you can use PowerShell to get it done quick:
Get-Mailbox -RecipientType ‘UserMailbox’ | Set-CASMailbox -MAPIBlockOutlookRpcHttp:$True
If you want to limit this to a special database:
Get-Mailbox -ResultSize unlimited -Filter ‘((RecipientTypeDetails -like ”*UserMailbox*”) -and (((Database -eq ”CN=DB_NAME,CN=Databases,CN=Exchange Administrative Group (FYDIBOHF23SPDLT),CN=Administrative Groups,CN=ORGANISATION,CN=Microsoft Exchange,CN=Services,CN=Configuration,DC=DOMAIN,DC=COM”))))’ | Set-CASMailbox -MAPIBlockOutlookRpcHttp:$False
You also can run this automatic via task scheduler.
Cheers,
Chris