Hi @FWFabio,
Can you please follow this guide Xcode exit code 65 / exit code 66 / raw-xcodebuild-output.log and check the IDE Distribution debug logs (attached by Deploy to Bitrise.io if you have that step in your workflow)?
If you could not find the reason of the error there, please send us the build URL through email / the onsite chat and we’ll have a look! (But first please make sure you follow the guide I linked above, and that you have the Deploy to Bitrise.io step in the workflow as described there)