Why cant i import stock acct data from td ameritrade or ally financial if have all the required passwords and account data. robinhood and schwab work

Hard to know...

Have heard reports that :

1)  2-factor authentication doesn't work, so that may need to be turned off first.

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or

...you might try changing those passwords to something simpler at the source, and then trying  (then change them back tomorrow.....not sure if the companies object to changing too often).

Have heard reports that:

2)  some special characters can't be used...like "! "   (but I have no idea which ones won't work)

call the FI's for assistance. they usually can tell you why you're having problems and how to resolve the issues.