After deploying Endpoint with network threat protection enabled it prevents us from being able to use our helpdesk software which uses sqlexpress database on a remote machine unless we try and open it about 50 times and then it eventually lets us in. If we temporarily disable threat protection there is no issue in connecting. I have tried putting rules in the firewall policy to allow all connections to the host but it just wont work! its becoming very annoying if anyone else knows of a workaround it would be greatly appreciated