Fixed intermittent error 5100 ("wait until the previous call has completed") while the add-in checks the email format. Calls are now serialized and retried.

Temporary Microsoft 365 hiccups during the permission check no longer trigger false "send as" errors — we now retry and only report a genuine denial.

Personalization tokens such as {{First Name}} that your mail client split across a line break or hidden formatting are now repaired before sending.