Please try using this direct link: https://intuitglobal.intuit.com/downloads/CanadaTax/2020/dls/TurboTax_2020.exe
You may also want to try a different web browser and see if that allows you to download. For example, if you are using Microsoft Edge, you can try Google Chrome or Mozilla Firefox instead.
If you are still having issues, please contact our phone support for further assistance. You can get the correct number by using this form: https://support.turbotax.intuit.ca/contact/