Some pointers...
1. Do always use the club number version of the list emails when using them in external services. Avoids problems from alias or domain changes over time.
2. Add external services domains to the club white list.
3. Set up the club archive email address... it can help w/ troubleshooting.
4. For testing, set up a custom group first and send to that.
5. When testing, always only send to members list first. If you abuse the system for sending to guests, prospects, former members, it reflects badly on the system (spam reputation) and we reserve the right to take action in that case.
For best results, split up email lists into separate emails.
Reason: Some email systems will send same email to FTH mutliple times for each address in To field. FTH does not require the multiple sends since it parses the separate addresses in one pass. FTH tries to detect multiple sends of the same email via caching of the Message-ID header in the email, but it is possible with atypical email senders (Google Calendar?) that its detection could be thwarted. If you can give me the raw source of one of the emails that Google Calendar sent out, I can take a look to see if the Message-ID header is still maintained.
Available references:
support.toastmastersclubs.org/doc/item/email-and-contact-forms
support.toastmastersclubs.org/blog/105-t...asthost-email-system
support.toastmastersclubs.org/doc/item/email-troubleshooting
support.toastmastersclubs.org/doc/item/email-from-mailing-lists
support.toastmastersclubs.org/doc/item/custom-groups
(If you whitelist the sending domain, you can ignore the bit about publically accessible FTH addresses--only do this after lots of testing though.)