TL;DR: your dash is too old for your werkzeug. Werkzeug 2.1 removed get_current_traceback and dash only fixed its import in 2.3.1. Upgrade dash, or pin werkzeug to 2.0.3.

## The error
```text
ImportError: cannot import name 'get_current_traceback' from 'werkzeug.debug.tbtools'
```

## Fix it
1. Upgrade dash to a release with the fixed import:
   ```
   pip install -U dash
   ```
   Expected: installs dash 2.3.1 or newer.
2. Verify:
   ```
   python -c "import dash; print(dash.__version__)"
   ```
   Expected: imports cleanly and prints the version.
3. If you cannot upgrade dash, pin werkzeug instead:
   ```
   pip install "werkzeug==2.0.3"
   ```
   Expected: the old name exists again and dash imports.

## When this applies
Use this when `import dash` raises this error and werkzeug is 2.1+.

## When it does not apply
If the error names a different werkzeug symbol, check what replaced it. If you do not use dash at all, find which package imports the old name and upgrade that package.

## Compatibility
dash below 2.3.1 with werkzeug 2.1+. dash 2.3.1+ works with modern werkzeug.

## Root cause
Werkzeug 2.1 renamed the get_current_traceback function to the DebugTraceback class. dash imported the old name at module load, so any dash older than 2.3.1 breaks the moment werkzeug is upgraded past 2.0.x.

## Edge cases
Pinning werkzeug at 2.0.3 can conflict with flask versions that need newer werkzeug; upgrading dash is the cleaner fix. Fresh virtualenvs avoid the half-upgraded state that usually triggers this.