Hi @Nathalie_Wer
When creating lists based on excel, the field names of the new list are created automatically during the import process and in most cases the internal column names will not then match the internal field names of your original list - this is where the issue arises as the app is then trying to reference fields that don't exist in your new datasource.
I would try to create a new list using the 'From existing list' option and choose the original list as your basis for teh new - this should then create your new list based on the exact same schema of the original list and once you switch to the new datasource, everything should work fine.
How much data is it? - if not too many rows, you could just do a copy and paste in edit in grid view between both lists. If it's quite a bit of data, you could create a simple flow with SharePoint 'get items' and 'create item' actions to automatically create the new items.
Another option is to save the original list as a template with contents included in the template. This is slightly more involved on the SharePoint side and you may need site collection admin to allow you to save the template. If you can manage with the approach above I would try that in the first instance.
Hope this helps.
