If you receive a message in Mail or Calendar for Windows 10 that your account settings are out of date, there are several things you can do to fix the problem.
Check your password
The most common cause of an out-of-date account is an incorrect password. Select Fix account in the notification bar at the top of the Mail or Calendar app. If your password is incorrect, you'll see a message asking you to update your password. Enter the new password and choose Done.
Tip: If you want to change the password for your account with your email provider—for example, Gmail or iCloud—you'll need to visit the website for your email provider. See Change your password for more information.
Check your security certificate
If your password isn't the problem, you may have a certificate error. If so, you'll see a message that says, "There is a problem with the server's security certificate. The security certificate is not from a trusted certifying authority."
This error often happens when you don't use SSL to secure your email account. To fix this error, use the following steps.
Choose Settings > Manage Accounts.
Choose the account that's out-of-date to display the account settings dialog.
Choose Change mailbox sync settings > Advanced mailbox settings. You may have to scroll down in the dialog to see Advanced mailbox settings.
Check the boxes for Require SSL for incoming email and Require SSL for outgoing email and then choose Done > Save.
Special instructions for other accounts
If you've enabled two-factor authentication on your iCloud account, you'll need to generate an app-specific password to add your iCloud account to the Mail app.
Sign in to your Apple ID account page.
Select Generate Password below App-Specific Passwords.
Follow the instructions on your screen.
Microsoft has added OAuth support for Yahoo! accounts in the Windows 10 Creators update. To install the Creators Update now, go to the software download site, and select Update now. For more information about the update, see Windows 10 Creators Update is here.
For additional steps you can take if your Yahoo! account can't sync with Mail for Windows 10, see I can't sync my Yahoo! account with Mail for Windows 10.
If you have a Japanese Yahoo! email account you will need to do the following:
You'll need to add your Yahoo! account as an IMAP account. To do this, follow the steps in Add an account using advanced setup above using imap.mail.yahoo.co.jp for your incoming mail server and smtp.mail.yahoo.co.jp for your outgoing mail server.
To sync your QQ mailbox with the Mail and Calendar apps, you need to enable IMAP on QQ.
Sign in to your QQ account.
Select Settings > Account > Enable IMAP.
Note: Your QQ account needs to be active for more than 14 days before you can enable IMAP.
In the Mail and Calendar apps, remove your QQ account and add it again.
Your QQ account should now sync automatically.
When you try to connect your GMX.de or WEB.de account to the Mail and Calendar apps, you'll receive an email in your GMX.de or WEB.de mailbox with instructions about how to enable access.
In a web browser, sign in to your GMX.de or WEB.de account.
Find the email message with instructions about how to connect your account to the Mail and Calendar apps, and follow the instructions.
Your account should now sync with the Mail and Calendar apps automatically.