Are you able to confirm that your base64 conversion used to work and that the resulting base64 was valid?
The app is still pre-users, so to be honest I can’t confirm it 100%
Looking at this logging data, I get the feeling it might have never worked to be honest.
It looks like fetching from the File Content URL using response type ArrayBuffer just returns a JSON with an empty data object.
I switched to response type JSON now, and I see the binary data inside the response. Now both types of requests fail, although with slightly different error messages.
Sending from server results in
FunctionEvalError: Invalid character
while the client variant results in
InvalidCharacterError: Failed to execute ‘btoa’ on ‘Window’: The string to be encoded contains characters outside of the Latin1 range.
The updated actions are on the mini-app I linked earlier.