Key problem. Unlock car only from close distance

[savi4s21]

Hello. Maybe someone can point me in right direction. I have mercedes w251 r class mercedes. Suddenly, couple days ago key not unlock doors from distance, only when close to driverside door ir sensor. I changed batteries in both key fobs but same problem with both keys. Any suggestions??? Is the problem with door handle infra red sensor or something else???
Thank you

 

[whitenemesis]

The IR sensor in the door handle is working as you say the door unlocks when close, so it seems the RF system has failed. As both keys with new batteries operate the same it would suggest the amplifier/antennae in the car has a problem. Get the error codes read using STAR