I am experiencing the same issue. I am receiving the same message: “Expecting value: line 2 column 1 (char 1)”.
I checked the different solutions you proposed but I keep receiving that message.
I’d appreciate a little help on this but it appears I can not upload my file as I am a new user.
Welcome to the community @fxc! Have you checked your xlsform with this site here. It should help you identify the syntax errors present within your xlsform.
If you however are not able to solve your issue, please feel free to share your xlsfomr with the community. The community would love to help you solve your issue.
Thank you @Kal_Lam, indeed using that website helped. Thanks.