Fail to login on Sql server with DNS but not with IP
I've also create an Alias on SQL Server


An alias is a client-side concept.  To be effective you must configure the alias on every client computer connecting to SQL Server.  The alternative is to create a Hostname Alias to enable that name to be resolved by all clients on the network.

There are four easy steps to creating a Hostname Alias, but they are poorly documented and often misunderstood. All you have to do is:

1) Create a DNS Record pointing to the IP address of the target server

2) Configure SQL Server to listen on port 1433 on that IP address

3) Add SPNs to enable the SQL Server Service account to use Kerberos Authentication (optional if you don't use Kerberos).

4) Add BackConnectionHostNames entries to enable NTLM Authentication

https://blogs.msdn.microsoft.com/dbrowne/2012/05/21/how-to-add-a-hostname-alias-for-a-sql-server-instance/