re: A drop down box appears saying SMTP Error.
I visited the site and sent a test message. This is the error message.
SMTP Error: The following recipients failed: [REDACTED]@gmail.com: Verification failed for Called: [REDACTED] Sent: RCPT TO: Response: no mailbox by that name is currently available [REDACTED]@connetions-pro.com is not a valid address: Sender verify failed
This message is coming from whatever plugin that is being used to configure SMTP support to send email. Connections/Contact does not send email on its own, it uses the core WordPress emailer (or a plugin if one replaces it) and then reports back any messages it receives back from the emailer, success or failure. On failure, it relies that message back to you.
In this case, the plugin configured to enable SMTP support and sending email thru Gmail seems to have a configuration error that seems to only manifest itself when you are logged out. I would expect to see the error whether logged in or not, honestly, so that is a bit odd.
I suggest using the Postman plugin to configure SMTP Gmail support since I know it works fine with Connections/Contact. If you have any any errors, perhaps it can help diagnose and resolve it for you.
Hope that helps, let me know.