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Common Issues and Troubleshooting

Solutions to common problems with the MUP Compliance App.

Cart Transform Issues

Levy Not Being Added

Symptoms: - Product added to cart - No levy appears - Price is below MUP floor

Solutions:

  1. Verify customer has selected Scotland as region

  2. Check product has custom.total_units metafield

  3. Ensure MUP enforcement is enabled in settings

  4. Verify levy product is published to Online Store

  5. Check browser console for errors

Wrong Levy Amount

Symptoms: - Levy is added but amount is incorrect - Doesn't match expected calculation

Solutions:

  1. Verify total_units metafield is correct

  2. Check minimum unit price setting (should be 0.65)

  3. Review product price

  4. Calculate manually: (units × 0.65) - price

Levy Added Twice

Symptoms: - Multiple levy line items for same product

  • Duplicate charges

Solutions:

  1. This should not happen - contact support

  2. Clear cart and try again

  3. Check for multiple cart transform runs

Validation Issues

Validation Not Added to Checkout Rules

Symptoms:

  • Validation function not blocking checkout

  • No validation errors shown

  • Function not appearing in checkout rules

Solutions:

  1. Go to Shopify Admin → Settings → Checkout

  2. Check Checkout rules section

  3. Verify "MUP Validation" function is added at checkout rules

  4. If not, add it following the setup guide

  5. Ensure function is enabled

Checkout Blocked Incorrectly

Symptoms: - Checkout blocked when it shouldn't be - Error message appears incorrectly

Solutions:

  1. Verify product total_units metafield

  2. Check minimum unit price setting

Checkout Not Blocked When It Should

Symptoms: - Order completes despite MUP violation - No validation error shown

Solutions:

  1. Ensure MUP enforcement is enabled

  2. Verify customer region is Scotland

  3. Check validation function is active

  4. Review product prices and units

Region Selector Issues

Selector Not Appearing

Symptoms: - Region selector not visible

  • Can't select region

Solutions:

  1. Check theme customizer settings

  2. Verify app embed is enabled

  3. Review CSS selector configuration f

  4. Check theme compatibility

Region Not Saving

Symptoms: - Select region but it doesn't save

  • Cart doesn't update

Solutions:

  1. Check browser console for errors

  2. Verify cart update is working

  3. Review cart attribute format

  4. Try refreshing page

Product Data Issues

Units Not Recognized

Symptoms: - Product has metafield but not used

  • Levy not calculated

Solutions:

  1. Verify metafield namespace is custom

  2. Check key is exactly total_units

  3. Ensure value is a number (not text)

  4. Verify product is saved

Health Check Shows Missing Data

Symptoms: - Health check reports missing data - But metafield exists

Solutions:

  1. Re-run health check

  2. Verify metafield on correct variant

  3. Check metafield value format

  4. Ensure product is published

Settings Issues

Settings Not Saving

Symptoms: - Click save but changes don't persist - Settings revert

Solutions:

  1. Check admin permissions

  2. Verify Shopify connection

  3. Refresh page and try again

  4. Check for error messages

Levy Product Not Working

Symptoms: - Levy product configured but not used - Error when adding to cart

Solutions:

  1. Verify product is published to Online Store

  2. Check variant ID is correct

  3. Ensure product is not archived

  4. Verify product is active

General Issues

Extensions Not Working

Symptoms: - MUP features not functioning - No errors visible

Solutions:

  1. Verify MUP enforcement is enabled

  2. Check customer region is set

  3. Review browser console

  4. Check extension deployment status

Performance Issues

Symptoms: - Slow cart updates - Delayed levy calculation

Solutions:

  1. Check network connection

  2. Review cart size (many items may slow)

  3. Check Shopify API rate limits

  4. Review extension logs

Getting More Help

If issues persist:

  1. Check Logs:
  2. Browser console for frontend errors
  3. App logs for backend errors

  4. Shopify function logs

  5. Review Settings:

  6. MUP settings configuration
  7. Metafield definitions

  8. Product data

  9. Test Scenarios:

  10. Simple test product
  11. Known good configuration

  12. Isolated issue reproduction

  13. Contact Support:

  14. Provide error messages
  15. Include relevant logs
  16. Describe steps to reproduce

Debug Mode

Enable debug mode to get more detailed information:

  1. Set custom.mup_debug metafield to true on shop
  2. Check console/logs for detailed output
  3. Review cart transform and validation logs

See Debug Mode for more information.