Prevent session as used Rds Trial 120 day on VM Windows Server 2012 R2

[Koong]

i have to checked daysleft. It show 43 day. It's only support 2 session.
I also try check everything is i know, Try reset RDS, Restart NIC, ... But it's not working.
I have purchased LC RDP per user Cal 2019 on MS . But can not add LC. It show pop-up invalid LC
I do not know how to fix it. Please help me!
Thank you so much!

[#2]

I have a question: License Rds 2019 do have support for Windows Server 2012 R2. I'm just reverify for ensure that is support