I finally fixed the problem!!!   

I use Yahoo mail , and all of a sudden I was unable to email statements, and invoices , also with attachments...I use QB-desk top pro 2020 

 1st... go to your email and go to the ACCOUNT SECURITY section

2nd...in yahoo go all the way to the bottom of page in ACCOUNT SECURITY... see manage app passwords

3rd ... you will need to type in Quick Books in the dropdown menu 

4th.... click enter it will give you a 16 letter pass word... COPY IT

5th Now go back to your QB and pick a customer to send a statement to

6th....now when it askes for the password to your email... PUT THE 16 LETTER PASSWORD THAT YOU COPIED INTO THAT BOX... and woohoo you are back able to email from within QB statements and invoices . 

Hope this makes your life easer, ..... P. Nicolay of California