Checks whether one address is excluded from your auto BCC. Returns 200 with the plain-text body OK if it is, and 404 with Not Found if it is not. An address counts as excluded when it is on your autoBccExcludedEmails list or its domain is in your autoBccExcludedDomains.

The check ignores case and also matches stored addresses that contain email, so [email protected] matches a stored [email protected]. Only your own lists are checked, not exclusions set by your workspace role. For an exact check that includes role exclusions, use POST /userpreferences/me/autoBccExcludedEmails/exists.