My washer has E:13 on the display. I called Bosch

According to the service manual, you should clean water drainage pipe and/or drain hose. Turn selector to off and restart 'drain, program or, on 500 plus machines, the 'refresh' program. It also says this is caused by using too much detergent. Bosch recommends using half of what the manufacturer recommends when using HE detergents. They don't recommend regular detergents. I would run the short wash or refresh cycle without detergent and hopefully your lines will clear. I have also read that if this persists, powder HE detergent is better to use instead of the liquid because of certain chemicals contained in the liquids that cause it to congeal in some front loader drainage pipes. I hope this helps.