Hi, I'm Robert and I'll be helping you with your computer question.
what you want to do is go to
file / account settings / account settings
you will get a window showing your accounts under the email tab
select the account that is not receiving emails
click the remove button on top
then click the add button
and put the account back in
you will need to know at least the email address and password
If you know the website where you can get those email messages from the provider it is a good idea to go there first and make sure that you can receive email there using the password ***** you have. If you can't get them there outlook will not be able to get them either and that would indicate a problem with either your password ***** the account itself.