Hi there!
I'm Louie, a Microsoft Community member and a fellow Windows 10 user like you. Hope you're doing well and safe there.
I suggest you to try this steps and see if it works:
Step 1:
- Open the Mail app.
- Click on Settings.
- Select Manage accounts.
- Click on your Yahoo account.
- Choose Remove this account from this device.
Step 2:
- Open any web browser (Google Chrome, Firefox, or any other that you regularly use)
- Sign in into Yahoo mail with your ID and password.
- On the top-right corner click on your name and choose Account info.
- In the next section, you need to select Account security.
- You’ll now have a new tab; towards the bottom of the page, click on “Manage app passwords”. click the same
- When a dropdown menu appears, you need to choose Other app.
- Click on “Generate“. Now, Yahoo mail will produce a 16 character password for your account. Copy the same.
- Now, reopen the Windows Mail app to fix code 0x8019019a.
- Go to Settings and then Manage accounts as you have done in the starting.
- Click +Add account.
- Note that this time, don’t choose the Yahoo option. Instead of that, select Other account (POP, IMAP).
- Type in your Yahoo email address
- When it asks for the password, paste in the 16 Char password you just copies from Yahoo.
- Type your Name and select Save.
Adding the Yahoo account this way did work for several people without getting Mail App Error code 0x8019019a in Windows 10.
Hope this helps.
Sincerely,
Louie