Hi @nattygur. I apologize for the problem. The Arduino Cloud developers have been notified of the bug.
For me, the problem only occurs when I am compiling the sketch from the "Sketch" tab of Arduino IoT Cloud. If I compile the sketch in Arduino Web Editor (AKA "full editor"), the problem does not occur. So this can serve as an effective workaround until the problem with the Arduino IoT Cloud sketch editor is fixed.
Please click the "Open full editor button and then try uploading your sketch again. Hopefully the problem will no longer occur.
Please let me know if you have any questions or problems while performing that workaround.
The bug that caused the unexpected "No such file or directory" errors when compiling from the "Sketch" tab of Arduino IoT Cloud should now be fixed. So it is no longer necessary to use the workaround I described earlier of using the "full editor" to compile and upload.
I'm going to ask you to post the full verbose output from an upload attempt.
This procedure is not intended to solve the problem. The purpose is to gather more information.
Please do this:
Select File > Preferences... (or Arduino IDE > Settings... for macOS users) from the Arduino IDE menus.
The "Preferences" dialog will open.
Uncheck the box next to Show verbose output during: ☑ compilation in the "Preferences" dialog.
Check the box next to Show verbose output during: ☐ upload.
Click the "OK" button.
Attempt an upload, as you did before.
Wait for the upload to fail.
You will see a "Upload error: ..." notification at the bottom right corner of the Arduino IDE window. Click the "COPY ERROR MESSAGES" button on that notification.
Open a forum reply here by clicking the "Reply" button.
Click the <CODE/> icon on the post composer toolbar.
This will add the forum's code block markup (```) to your reply to make sure the error messages are correctly formatted.
Press Ctrl+V.
This will paste the error output from the upload into the code block.
Move the cursor outside of the code tags before you add any additional text to your reply.