Time Machine Stuck on Preparing Backup in macOS 10.14.
Apps Freeze or Quit Unexpectedly on macOS 10.14.
Merge and Remove Duplicate Contacts on macOS 10.14.
Remove and Rearrange Menu Bar Icons on macOS 10.14.
Download YouTube Videos Free on macOS 10.14.
Edit Photos with Preview in macOS 10.14.
Method to Back Up Data on Mac before Updating into 10.14.
Contact your email account provider to verify your user name, password, incoming mail server, and other required information then verify the information is entered correctly in Mail account preferences.
If you’re logged in to a network using VPN, make sure that you entered your VPN password correctly.
Contact the appropriate person for information. Check whether you’re affected by another firewall, such as software installed separately from macOS or built into an Internet sharing router, or administered by your email account provider. Check for problems logging in to email accounts or with the incoming mail server, or with firewall software blocking network traffic.
Choose Window > Connection Doctor, then follow any instructions in the Details column.
Try quitting Mail, then opening it again.
Check whether your account is offline or disabled (inactive).
Try sorting messages in the message list by Date or another attribute, or searching for messages, to verify if you received them.
Check if you’re using filters in the message list that are preventing expected messages from being shown.
For more information, see View Mail activity.
Check whether Mail is retrieving a large message or a message with large attachments.