/for-email-admins/spamstop-app/client-side-sender-filter/ to receive in your inbox only the senders you have previously authorized Hugo en /for-email-admins/spamstop-app/client-side-sender-filter/microsoft-365-outlook/ Mon, 01 Jan 0001 00:00:00 +0000 /for-email-admins/spamstop-app/client-side-sender-filter/microsoft-365-outlook/ in outlook settings enable: trust email from my contacts /for-email-admins/spamstop-app/client-side-sender-filter/mozilla-thunderbird/ Mon, 01 Jan 0001 00:00:00 +0000 /for-email-admins/spamstop-app/client-side-sender-filter/mozilla-thunderbird/ in Thunderbird create a filter with rules 'From isn't in my address book'