Hi Richard Plummer,
Let's do the basic browser troubleshooting steps to check if this error is caused by a full cache.
A good start is to log in to QuickBooks in a private browser. If you can set up your MTD without error, please go back to your regular browser and clear the cache. If not, please try other browsers like Chrome, Edge, Safari, or Mozilla Firefox to isolate the case.
If you get the same error after trying everything, please contact our phone support to check this further. They have more tools to check it.
- Click on Help and choose Contact us.
- Enter a short detail of the scenario and click Let's talk.
- Choose from Chat or Get a callback.
We'll be around if you have other questions.