No.  Check your connections.  Make sure the 3.5 mm cable is stereo (2 black lines on the connector instead of 1) and make sure it is pressed all the way into the connector.  Also make sure the RCA connection to the turntable are in the correct outputs and pressed all the way in. 

You say “they are grouped”. If you have the Eras set up as two rooms, rather than having them stereo-paired as a single room, the behaviour is “normal by default”. When you play the turntable as a source, it will be to that room/speaker only. You can group the other room/speaker and then they’ll both play. I think you can also turn off the Ungroup option for line-in input. (I’m away from my system atm so can’t confirm that.) If they are stereo-paired and only one is playing, there is a problem with a first step solution per ​@jgatie’s post. 

After restarting the 2 Era 300, now it works fine ! I can hear the turntable on both speaker !