Intermittent undeliverable email

On weekends and intermittently over the past three weeks using the member and officer email address we get rejections. I'm guessing the site is down on weekends or has capacity issues?

Subject: Undeliverable: We need speaker today!!! Challenge yourself!!!!

The following message to <members-9010@toastmastersclubs.org> was undeliverable.
The reason for the problem:
5.4.7 - Delivery expired (message too old) 'timeout'

I know you're volunteers, but if you can post outages then we might know for sure if it is our IT or your IT.

This is different from the Junk email issue which can happen with any email provider.
Thanks

Fiona

Who sent the email? first name or officer position?
Approximately when did they send the email?

I can see Melisa, Joan and Robert all sent the email. The emails were sent on Wednesday Wed 2019/01/23 19:24:25 UTC, Our server received and sent the emails.

You are sending to government work email addresses, are all the destinations failing or just one?

I see no emails being sent with that subject on Sunday Jan 27, 2019

Club: 3733

I am seeing the same issue. Last night (1/28), I sent to Officers@NoviToastmasters.com and the connection timed out:
This is the mail system at host gproxy2.mail.unifiedlayer.com.
<officers@novitoastmasters.com>: connect to
mail.novitoastmasters.com[50.19.253.65]:25: Connection timed out

Over the last week or so, I have seen this on email to members also. It is always a timeout but if I send again, it goes through.

What IP is gproxy2.mail.unifiedlayer.com pretending to use.

1) gproxy2.mail.unifiedlayer.com. is not a valid subdomain
2) you need to be sending email from valid domain with corresponding valid MX records, and spf records.

Brian,

I am sending email from the same account as I do for many emails all day. (It is my own hosted server. and is set up correctly.) Also, as I stated, it will timeout once then send fine the next time I send the same email. If this was a misconfigured sending server, it would never work. FTH is the only email I have this issue with. The timeout is with the FTH server: mail.novitoastmasters.com[50.19.253.65]