One of my Apple Mail accounts doesn't fetch new mail
I have four accounts set up in Apple OSX 10.14.6 Mail. One iCloud, two @Verizon.net (AOL hosted), and one @gMail.com. All are set up as imap accounts. Mail periodically fails to fetch mail from the one of the @Verizon.net accounts that I use most often. I realize this when I receive a new email notification from this account on my iPhone and then can't find it in Mail on my iMac. I usually can break the blockage by exiting and relaunching the Mail application. Sometimes it works to go to System Preferences>Internet Accounts and uncheck the "Mail" checkbox and recheck the checkbox. The other @Verizon.net account, although not used as often, doesn't seem to exhibit this behavior. Any ideas how to resolve this annoyance would be appreciated.
iMac 27″, macOS 10.14