With the greatest of respect, Howard, what that may suggest - all other things (network issues, possible contentions, versions and so on) being equal - is that you are perhaps experiencing some of the teething troubles due to the specifics of Apple’s latest macOS iteration.
And, again, not to downplay your experience:
only really suggests that you probably do not have apps which may so far be experiencing those teething troubles installed.
Did you do as @Connor asked?
Have you read this thread?
Did you follow @Jake_Davis’s advice?