Hi there, jleeor.
There are times that the browser keeps outdated Internet files that may cause websites, like QuickBooks Online, to receive unusually error message.
I suggest logging in your QuickBooks using incognito browser to rule out the possibility of a webpage issue. Private browsing doesn't store local files or cache.
Use these keyboard shortcuts based on the browser you're using.
For Internet Explorer of Firefox, press Ctrl + Shift + P.
For Chrome, press Ctrl + Shift + N.
For Safari, hold down Command + Shift + N.
If it works in incognito, clear the cache of your regular browser. Doing this helps QBO to function more efficiently.
If the steps above will not work, you can use supported browser as alternatives.
Please know that you're always welcome to post if you have any other concerns. Wishing you and your business continued success.
Thanks for the prompt response, jxx.
I appreciate your providing additional details. I recommend contacting the HRMC. They have tools to review your user ID and make sure you can submit your tax return seamlessly.
This link will route you to the HMRC website: https://www.gov.uk/contact-hmrc
Get back to me if you need further help. I'm always happy to assist. Have a great day ahead!
We have had other users contact our care team today with the same message and this is what we have been advised when we have queried with HMRC and the tier 2 engineer for VAT/MTD.
If you do have the same message tomorrow please reply back here in the Community and we certainly escalate this to them however.