Hi Safa Mashat, the problem with the two lights, can have several origins
First, disconnect the signal that enters these two channels and check if they are still on, but they are, the problem is in the cable or device that is connected to that line
If the fault still continues, it is most likely that the two-channel input stage has been damaged.
In this case if you have technical knowledge, I send you the service manual link
If not, I suggest you look for a specialized technical service
I hope you can solve the problem
Greetings Franco Dosil

Hola Safa Mashat, el problema que tenga las dos luces, puede tener varios origenes
Primero, desconecta la se?al que le entra a estos dos canales y verifica si siguen prendias, sino lo estan, el problema esta en el cable o aparato que esta conectad0o a esa linea
Si aun continua la falla, lo mas probable que se haya da?ado le etapa de entrada de los dos canales
En este caso si tienes conocimientos tecnicos , te envio el link del manual de servicio
Sino, te sugiero buscar un servicio tecnico especializado
Espero puedas resolver el problema
Saludos Franco Dosil

https://elektrotanya.com/yamaha_emx5016cf_sm.pdf/download.html
https://mx.yamaha.com/files/download/other_assets/5/334285/emx5016cf_es_om_d0.pdf