Flywheel hosted WordPress website goes down after Marketo email send

[Bonnie_Jeffers2]

I realize this is a long shot, but thought I'd check here as well.

We don't send lead gen campaigns daily. However, coinciding with the last couple sends (no more than 32K recipients each) our website has gone down. They don't seem at all related, but here's the correlation:

Email send: October 17, 2019, at 10:00 AM ET - website down by 10:07 AM ET
Email send: October 17, 2019, at 11:00 AM ET - website down by 11:01 AM ET
Email send: October 22, 2019 at 1:00 PM ET - website down at 1:03 PM ET
Email send: October 24, 2019 at 7:30 AM ET - website down at 7:33 AM ET

We're on a shared Marketo IP pool for email sends.

Website is developed in WordPress environment and hosted by Flywheel. WordPress core updates controlled by Flywheel (so I've been told).

Marketo forms are embedded on the site.

Unfortunately, our WordPress developer/website owner moved on to a new opportunity a few weeks ago. To my knowledge, we've never had this email send/website down situation before. Do you guys have any clues here? Could this be a patch or update issue with WordPress possibly? We definitely have a skill gap right now and I'm concerned because this is starting to look like a pattern.

We have a support cases submitted with Flywheel and Marketo, but haven't heard anything yet.

Thanks in advance for any thoughts on this.

[SanfordWhiteman]

It's very simple to make this happen.

If you have a broken asset URL (i.e. image URL) in your emails, then the requests will all go to your fallback page. Most people have their fallback page set to their website. Ergo you end up with everybody requesting your homepage.

Of course the site going down from 32,000 requests isn't a good sign for its resilience.

[Bonnie_Jeffers2]

Thank you, Sanford. That's not our issue, but I love that nugget of information. I had never thought about that scenario before.

[SanfordWhiteman]

If it's not that, then it's just coincidence.