Web based outlook mail not finding many outlook people contacts

Having trouble with web based Outlook Mail and Outlook People contact list.  When I try to create a new email and enter most existing names in the People contact list into the "To:" field, then Outlook mail do not find them.  It does work for some entries, but I can't see why.

I can create a new entry, and it finds it correctly.  I have exported all the people contacts, deleted them from people, then re-imported them, but this does not solve the problem.  Have also tried other browsers and it fails.  It works on another computer successfully.

This is a recent problem, maybe after the last Windows anniversary update?  Also noticed my Outlook mail filter list was defective, and have had to re-add filters.

Any suggestions?