7 years later.... and this still works.
Windows Server 2022 Std. with Microsoft SQL 2019 Std.
Windows (x64) NetXMS 4.0.2092.
(1) Install SQL First
(2) Set named pipes in sql config
(3) Launch a cmd and run the commands listed by Toepfe
(4) Run the windows netxms installer with making your db name match your created db (mine was just netxms)
Settings for install were....
Database Type = Microsoft SQL
Database Server = YOURSERVERNAMEONLY
Database Name = netxms (or whatever you named your db in the commands above)
Login Name = sa
Password = (your sa password, if you use sa)
No check in the box for Create database and database user before initialization