@bert_hubert yes, it's a big privacy and security issue with Microsoft's mail hosting. I have to use https://addons.thunderbird.net/en-US/thunderbird/addon/unmangle-outlook-safelinks to avoid Microsoft learning about links/URLs that I click on, also many that are used within the corporate intranet and should not really be exposed to the outside. (Doesn't really matter when Exchange isn't on-premise anymore though.)