Genuine emails getting redirected to junk/spam

Hi. We recently moved our hosting to Outlook.com, but discovered after a week that a significant (30+) number of genuine emails were getting automatically moved to the junk (spam)  folder. We can only access the spam folder via the web client, as when using a PC/Mac mail client (eg Outlook for Mac etc, - I am on Outlook for Mac 2011 14.3.7, but mail clients used vary) these emails don't get sent to our email clients (using POP) - which means that we have missed several important emails as we generally check email via the Outlook for Mac etc, not the web client.