I've been using a program called "CSV2QFX" to convert ".csv" file to a ".QFX" file for many years. A few days ago, I began receiving the message from Quicken "Quicken is currently unable to verify financial institution information for download".
After many days of frustration including a call to Quicken technical support (they couldn't help), and much trial-and-error, I resolved it!
Here's how:
Pull-down: "set account ID and type" set this to "checking"
"Quicken target" set this to "regular QFX"
This works every time!
I hope this saves someone else 4 days of frustration!