As I mentioned above, I used "Connect to PayPal" then "Let's do it". But it didn't work. 

* I wrote "Chart of Account >PayPal Bank > Reconnect (Under Action) > Connect to PayPal > Let's do it > Give Permission" in my original post. 

I connected PayPal and QBO once but for several different reasons I had to disconnect.  Then I wanted to reconnect. So I went to Chart of Account page > PayPal Bank > Choose "Connect Account" (Under Action) > Connect to PayPal.  It didn't work. 

If PayPal bank got disconnected once, it cannot be re-connected anymore?

And also I read somewhere to say "if the PayPal was connected to other account, it would't connect. "

Is it true?