Only do this if you have forgotten or lost your cross signing backup passphrase.
Please read through the entire document before starting to make sure you understand the consequences of doing this.
You may wish to backup your keys before doing this just to be on the safe side if something goes wrong: See Export and Import E2E Room Keys
Go to Element Security & Privacy settings
Security & Privacy
Click Reset cross-signing and secret storage
Reset cross-signing and secret storage
Click Clear cross-signing keys
Clear cross-signing keys
Click Generate a Security Key or Enter a Security Phrase. Then Continue
Generate a Security Key
Enter a Security Phrase
Take note of your key then click Continue
Enter your account password and click Continue
You can delete any untrusted sessions in Element Security & Privacy settings. Select the sessions you want to remove and click Delete 1 session
Delete 1 session
Doing this will destroy all your keys and you will NOT be able to access any historical encrypted messages.
Log in to Element
Click Skip again
Do not connect to Key Backup or verify session when asked
Note that you will not be able to decrypt any previous messages after doing this
Follow the steps from If you have an active session