Yes, this does sound like an issue specific to this server or hoster to me as well. Either the hoster is somehow blocking access to those URLs (more likely), or Amazon blocks this server from accessing those (less likely).

I tried importing that ASIN on my local site and it went through without problems or errors. The quickest way to narrow this down and say for sure whether it’s something about that server/webspace or about your site (like other plugins) would be to clone the site to a staging server and see whether it works there.

We do this frequently to narrow a problem down – or as proof that a specific problem is indeed related to a specific webspace – using the service of WP Stagecoach by the way. If you want us to do that, please contact us using the support form on wplab.com or directly via email at support (at) wplab.com.

kind regards,
Matt

Well, it doesn’t have to be Amazon returning this error. All we know is that a PHP script on your server (WP-Lister, using actually a function in WP to fetch an external URL) is trying to fetch that URL (the Amazon product page) and instead of the page content it only receives that 503 error message.

Now that can mean that Amazon is actually returning this error message, but it could also mean that your hosting provider has some kind of filter or firewall in place that blocks this request (so it never actually reaches Amazon’s servers) an returns the 503 instead. I’ve seen this many times, for example on servers with mod_security installed – in which case the error message isn’t to be taken literally at all.

That’s why the easiest thing to determine whether it’s your server or not, would be to test it on a different server. It’s also the best argument you have when talking to your hosting provider: Usually they’ll reply something about the script or plugin being the problem and that they can’t debug 3rd party code (or words to that effect). But if you can tell them “We cloned the site to a different server where it worked just fine, so the problem is with this server / your infrastructure and unless you can’t fix it we need to move to a better hoster.” that’s usually much more effective in getting this fixed.

Regarding your question: No, I simply imported the ASIN directly, not by processing a report. Of course, the end result would be different (regarding the SKU), but there is no difference at all about the process and about fetching those URLs. If there was a problem with that specific product that would trigger that error somehow, then I would have seen it myself. But there isn’t anything wrong with WP-Lister and you shouldn’t see that error message, that’s for sure.

I’d highly recommend you contact support directly so we can investigate this properly. This public forum isn’t the right place to solve this kind of server specific issues.

kind regards,
Matt