Checks an address against its real mail server and shows the conversation behind the verdict.
Identity sourcesmicrosoft offgoogle —
Durable — paste once, no re-pasting.
A Google token mints fresh sessions on its own, indefinitely, so the
credential never needs refreshing by hand. It works until the account
password changes or you revoke it at
myaccount.google.com/permissions. Use a throwaway account:
this token is full account access.
To get one, sign the account in at
accounts.google.com/EmbeddedSetup, click through to
I agree, then DevTools → Application → Cookies →
copy the oauth_token value (starts oauth2_4/)
and paste it below. The server exchanges it for a durable token
automatically. An aas_et/ master token works here too.
Stored mode 0600, never logged, never returned by any endpoint.