If you rely on email notifications when people RSVP and/or want people to get a confirmation and reminder messages, version 2.7.4 should be able to do that more reliably if you provide an email server and account to be used for notifications. You enter these on the Settings screen. After you save the parameters, click the link to send a test email to make sure it works.
You can create an email account for this purpose on your web server, or use a GMail account (limit: 500 recipients per day), or SendGrid account (specialist in high volume notification emails, free for up to 200 emails per day, reasonable prices for higher volumes), or use any other SMTP server you have access to.
All notifications will then come from that account, and having them come from an authenticated account should help you get past spam filters and precautions your web host takes to avoid hosting spammers. The replyto address will be set to the email address supplied by the attendee for notifications. Confirmation messages sent to attendees will have the email address you specified for notifications as the replyto address.
The parameters you need to enter are:
SMTP server type – select GMail, SendGrid, or Other from the drop-down list.
Email account for notifications – example email@example.com
Email username – firstname.lastname@example.org (on some servers, it could be “notify” or something different from the address)
Email password – Enter the password. Think through the security implications (maybe you don’t want to have the password for your primary email account stored here)
Server, Prefix (ssl or tls), Port # – Not necessary to enter these for a Gmail or SendGrid account.
I’d have done this sooner if I had realized that the PHPMailer utility was bundled with WordPress, a fact I just stumbled across while looking at the WP Mail SMTP plugin (which allows you to modify your site to use SMTP for routine WordPress notifications such as account signups). Previously, I suggested a customization based on the PHP Pear module, which works well but is not enabled on every web server.