• Method 1. Modify Send/Receive Settings.
    1. From Outlook 2010, 2013 or 2016 main menu,* click the "SEND / RECEIVE" tab and then expand Send/Receive Groups.

    * In Outlook 2007 go to: Tools –> Send/Receive –> Send/Receive Settings.

    2. Uncheck the "Disabled Scheduled Send/Receive" option.

    3. Restart Outlook and check if Outlook performs the automatic "Send/Receive" operation at startup or when using the program. If not, then continue to next step.

    4. From Outlook 2010, 2013 or 2016 main menu, go to File –> Options. *

    * In Outlook 2007 go to: Tools –> Send/Receive Settings –> Define Send/Receive Groups. Then continue to step-6

    5. Click Advanced on the left and under the Send Receive section, click the Send/Receivebutton.

    6. Click New.

    7. Type a name for the new group (e.g. "My Group") and click OK. 

    8. At "Send/Receive Settings" check the "Include the selected account in this group" and click OK. *

    * Note: If you 're using more than one emails accounts, then perform the same action to all the listed accounts.

    9. Then  highlight the new group (e.g. "My Group") and make sure that the "Include this group in send/receive" checkbox is selected and additionally ( if you want) specify how often you want Outlook to auto Send/Receive messages (e.g. Schedule an automatic send/receive every 30 minutes) .

    10. Then highlight the "All Accounts" group and click Remove. *

    * Note: If you cannot remove the 'All Accounts' group then uncheck the "Include this group in send/receive" checkbox below.

    11. Close "Send/Receive Groups" window and restart Outlook.

    Don't Miss : Outlook Not Working

    Method 2. Repair Microsoft Office.
    1. Navigate to Programs and Features. To do that:

    1. Press simultaneously the Windows  + R keys to open the run command box.

    2. Type: appwiz.cpl and click OK.

    3. In Programs and Features, select the Microsoft Office product that installed on your system and click Change.

    4. Finally click Repair and follow the rest steps to repair Microsoft Office. *

    * Notice: If after clicking Repair, you receive the "How would you like to repair your Office Programs" screen, select the Quick Repair option, which checks and replaces the missing or corrupted files. If after the "Quick Repair", the problems doesn't fixed, then choose the Online Repair option to reinstall your Office product. (requires an Internet connection)