Troubleshooting: when the app will not run

Python not found, Gradio not installed: you will hit these. Solving them yourself is the start of the debugging muscle.

How to read an error

The machine does not guess. Read the last line of the traceback, find it below, try the fix once. Log the exact error, what you tried and what fixed it.

01The Errors You Should Expect

python is not recognised / command not found

Cause

PATH not set during install (Windows), or Mac uses python3.

Fix

Windows: reinstall and tick Add Python to PATH. Mac: use python3 and pip3.

No module named gradio

Cause

pip installed into a different Python than the one running.

Fix

python -m pip install gradio

So pip and python match, then run again.

Address already in use / port 7860

Cause

The previous app is still running.

Fix

Close the old terminal or press Ctrl+C in it, then run again.

IndentationError / SyntaxError

Cause

A line was pasted with wrong spacing or a missing quote or bracket.

Fix

Re-copy the template exactly; Python counts the spaces at the start of a line.

Browser shows nothing

Cause

The URL was retyped wrong, or the terminal was closed.

Fix

Click the link the terminal printed; keep that terminal open while you test.

def, return and functions are unfamiliar

Cause

These lessons do not teach Python syntax.

Fix

Finish the Python bigbinary prerequisite first.

02Still Stuck

Under 20 minutes in	Read the last line of the traceback, check the list above, try the fix once.
Same error after 20 minutes	Ask for help (a peer, a forum, an AI assistant) with the exact error, what you tried and a screenshot. The help-post builder formats it.
You fixed something	Add it to your error log, and share it if you learn with others. Your fix is someone else's blocker.

First-time coders: pair up, and keep the beginner kit open.