I’ve been having the same issue of Export Failed. I’ve double checked my form design both for duplicates in names as well as repeats but I can’t seem to find the mistake.
I’ve also verified the form on https://getodk.org/xlsform/ to check for syntax errors. I can download the data as XLS (Legacy), but would be very grateful to have some help finding the error.
I took the liberty to send you my information on a private message.
Thanks in advance.