Orange name (instrument disabled) how to enable again?

Hello, some times, when I open a project, I got some of the instruments disabled, with orange letters as when there is freezing instruments, but in this case, I have non freezing instrument, also if I click in the little icon to open the VST I can see it (example Sylenth1) but there is no sound and as I said: Orange “sylenth1” letters like in the attached image
Captura de pantalla 2018-12-20 a la(s) 7.22.32.png
¿how can I enable again?


When you close and reopen the project, is it fixed?



I’m thinking what does the orange color coding means in this case. And I have no idea.