Joe Worksman Post Office stack slow to connect to Sendy

On my main server, Joes Post Office stack is super slow to connect to Sendy for newsletter subscriptions. Like 2-3mins instead on more or less instant.

All other forms connect in the usual fast time. Just Post Office having issues.

I’ve tested Post Office on my other servers, and it’s working, it’s just the main VPS that is having this issue, and it’s all sites using the stack too. So, I don’t think it’s a problem with the stack.

My server guy has been all over things, we can’t see any reason for the issue.

One example of the form is here (scroll to footer):

We are looking into things, but I’d welcome the input from anyone with any ideas, as we’re running out of them!

The plot on this one thickens…

Just republished, didn’t change. But, in preview it’s working 100%. It’s only the published site that exhibits the issue.