The latest version of the bitwarden firefox extension seems to impact non-modern zimbra webmail. IN fact when I click on the email, nothing is displayed, when uninstalling the extension, I recover the display of the normal email, this seems to be a problem with the action configured in the autofill tab
@RavenRAMIREZ Hi!
There lately were already some threads involving Zimbra - in the hope, that may help you: