Hi @anna1,
Welcome to the community! Looking at your error message, it seems that in one of your questions (in the survey tab, row 10) you have mentioned to select choices from iy1cf35 but looking at the same in the choices sheet (i.e. under the list name) iy1cf35 is missing.
As a quick workaround, download your xlsform from the KoBoToolbox Form Builder User Interface following the instructions outlined here and then quickly scan for what i have highlighted. Fix the issue, replace the xlsform and then redeploy/deploy the survey form. Your issue should be solved.
Have a great day!
