Same problem here.
I can auto-fill one person from CRA, then the next try will get timed out.
I waited a couple of days, then I got the first auto-filled with no problem and the second one timed-out.
When signing into CRA account using the multi-factor authenctication, you are asked to input the one-time passcode. Don't hit 'enter', scroll down the page and click 'next'.
No more timed-out issue.
I have the same issue - it auto-filled the first person; and when I proceeded to do the second person, CRA displays an error message "Session timed out". I signed out of CRA, Signed out of Turbo Tax, and started again - same thing. We have so many slips, and really hoped to use this feature to avoid entering numbers into numerous fields - that's where errors can occur. How can this be resolved?
I have done this, and then chose the option not to ask for a passcode (it allows for 8 hours). And it still says session timed out.
Same issue, trying to load ~225 slips and keep getting the "Oops, we encounted an error" message after I connect and everything downloads from CRA. Clearly this is an issue on the TurboTax software/serve side because this is well below the 500 slips the CRA has set as a limit. Please fix your servers TurboTax.