The DHL Express rates are not visible in the checkout, or the "not available" message is displayed.
- Make sure the module and the SDK are up to date. Note that they have different versions.
Check the file composer.lock in Magento's base directory and compare with:
- Use Composer to update the module and the SDK.
- Is the DHL Express module enabled in Magento in the section "General settings"?
- Are the sender and receiver addresses valid? Don't use test-data. Use fully valid addresses that really exist.
- Does the product in the shopping cart have a weight? This is required.
- Check the API credentials. The DHL Express support can verify if incoming API requests are ok.
- Is the shipping origin fully configured in Magento in "Configuration -> Sales -> Shipping settings -> Origin"?
- Is the receiver address in an excluded country? Configuration: "Applicable Countries / Allow for Specific countries".
- Are DHL Express products enabled in "Allowed International / Domestic Products"? Not all products may be available for a given destination.
Have a look at the official documentation.
Set the log-level to "Debug", go through the checkout again, then look into the log. It may indicate what the problem is.