Google is increasingly "rate-limiting" emails from known bulk senders such as WildApricot. That means they block emails for gmail subscribers who have recently had lots of messages from other bulk senders. What this means in practice is that an increasing number of failures on messages you send to your members. For entirely informational messages, there is a spiffy resend to failures feature that will cause WildApricot to resend the rejected message to the subset of failed recipients. Unfortunately it doesn't work for registration invitation emails because the Resend to failures facility can't expand the register buttons macro. WildApricot could easily trap this situation and give us a modified Resend to failure feature that specifically was enabled to expand the macros. The percent of rate-limited gmail fails is increasing from week to week — now nearly 4%.