10.3 - Failure to access the DBMS server

[AndyArismendi1]

I must be missing something here but I can't get ArcCatalog to connect to SQL Server.

Here's my setup (all fresh installs) -

- Database VM

   - Windows Server 2008 R2 x64 (not on a domain)

      - SQL Server 2008 R2

   - ArcGIS Desktop 10.3

- Client VM

   - Windows 7 x64 

      - ArcGIS Desktop 10.3

      - SQL Server 2008 R2 Native client x64

I've tried to run the Create Enterprise GeoDatabase tool and use Add Database Connection to connect and both fail with error "Failure to access the DBMS Server".

I have SQL Server setup for mixed mode authentication. I created a database account with the sysadmin role. I can connect on the database VM with windows authentication using SQL Server Management Studio and using the "admin" account with database authentication. On the client VM I can also connect with SQL Server Management Studio using database authentication. So I think SQL Server is OK... I installed SQL Server with all features enabled.

Here is the python snippet of what I'm trying to connect with on the database VM -

arcpy.CreateEnterpriseGeodatabase_management(database_platform="SQL_Server", instance_name="localhost/MSSQLSERVER", database_name="sde", account_authentication="OPERATING_SYSTEM_AUTH", database_admin="sa", database_admin_password="#", sde_schema="SDE_SCHEMA", gdb_admin_name="sde", gdb_admin_password="*****", tablespace_name="", authorization_file="C:/Program Files (x86)/ESRI/License10.3/sysgen/keycodes")

So what's wrong here? The error from ArcGIS is not helpful. 

[arahman_mdmajid]

I wanted to add to this that some time long and unusual database names give out these errors. I changed the database name to a simpler form and resolved the issue.

https://support.esri.com/en/technical-article/000005892

[JeffLegato1]

My problem is not related to the solution here but I wanted to post these links in case anyone else ended up here searching for:
arccatalog 10.8.1 "failed to connect to database" "failure to access the dbms server"

It's important to have the correct ODBC drivers installed depending on which version of SQL Server you are running. If SQL 2022 then you need ODBC v 18. If earlier version of SQL (we were using 2016) then you should use v17. 
https://enterprise.arcgis.com/en/system-requirements/latest/windows/database-requirements-sqlserver.... 

https://desktop.arcgis.com/en/system-requirements/latest/database-requirements-sqlserver.htm 

[George_Thompson]

I have experienced this same behavior also with different version of the ODBC drivers.