You can try putting the call in your Rule into a try/catch but given that the log statement is a warning level and there is no stack trace I suspect there isn’t an exception thrown.
In which case, you could work around this by using the LogReader binding to watch the log. Set a timer to wait a minute and if the LogReader binding saw that warning, try sending the email again. Using Design Pattern: Looping Timers might be a good idea.