Hi @Tal Bracha
Based on your description, this may be because Microsoft recently introduced a new feature that allows Outlook emails to open next to web links in Microsoft Edge by default.
For this reason, the official documentation provides a way to turn off this setting: File > Options > Advanced > File and Browser Preferences and select your preferred browser from the drop-down menu.
More information, please refer to: Outlook emails open next to web links in Microsoft Edge - Microsoft Support.
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