We, the SBB Community, are aware of this issue and, according to the statement from @RomanoS, SBB is about to work on a resolution. Since this is a technical glitch, you can ask SBB to alter your date of birth.
For short-term travel, kindly contact the SBB Contact Center, +41 51 225 78 00. Have your tickets ready as you will need the ticket number.
In case your ticket is valid later this year, you could also ask for a rectification in writing (allow at least 10 workdays): Claims and complaints | SBB help & contact