Hi @Marcos Moreno ,
the RDS Manager snap-in was removed by Microsoft in Windows Server 2016.
Maybe one if the links is helpful:
http://woshub.com/how-to-run-tsadmin-msc-and-tsconfig-msc-snap-ins-on-windows-server-2012-rds/
https://asenger.de/blog/how-to-run-tsadmin-msc-and-tsconfig-msc-snap-ins-on-windows-server-20122016-rds/
https://www.lemonbits.com/remote-desktop-services-manager-2016/
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(If the reply was helpful please don't forget to upvote and/or accept as answer, thank you)
Regards
Andreas Baumgarten