Most of my messages go to my Important box and the others don't arrive at all.

Since I cleaned out my temporary files and added one rule (done at the same time), my incoming messages stopped arriving in my Inbox in Outlook -- sporadically at first, now not at all.  For the past few days many of them go to my Important folder, and others don't arrive at all.  My sent messages all appear correctly in my Sent folder.
I checked the few rules I had, and they were fine.  Just to be sure, I deleted all my rules but the problem persists.
All my messages arrive normally on my cell phone and in the Gmail app.
Help!  Thank you.