We have discovered an issue with our "Add to Outlook" feature that no longer works and is creating a non-stop duplication problem causing our servers to run at 100% CPU and slowing down or crashing email services. If you use Microsoft Outlook with our service, please check to see if you are using our "Add to Outlook" feature and remove it. This will ensure that our servers run stable and fast for everyone so please remove this feature ASAP.
Currently we offer Outlook Sync to synchronize Webmail Email, Calendar, Contacts, and Tasks with Outlook 2019 / Microsoft 365 and Outlook 2016.
The instructions here may very depending on the version of Outlook you are running but will be similar in all.
Please go to File -> Info -> Accounts -> Account Settings.
In the Account Settings popup, go to Sharepoint Lists -> find your calendars, contacts, and/or tasks and remove them.
Login to Webmail, go to Settings -> Connectivity -> Open any "Add to Outlook" you see here and delete it.