Plugin not working at all

Thanks for reaching out, hopefully we can assist. From inspecting your sites source code I noticed some page optimizations are performed, with what looks like a Swift plugin. Did you install this or make any changes recently? Please try and temporarily deactivate this plugin before checking once more for the same issue.

Should the same 404 pages exist please share your Site Health information here or privately using this form and we can check your current setup.

Disabling Swift did not resolve the issue.
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PHP log won’t paste inside your form.

Thanks for sharing. There are a lot of plugins active, making it more difficult to troubleshoot. Do you recall any changes made to your site or third party plugins when this started to occur, this could include any manual updates from when your AMP URLs worked previously?

One troubleshooting step you may wish to perform is to switch temporarily to transitional mode AMP and check for the same issue. Your active theme has an AMP compatibility plugin allowing your jQuery based navigation menu to work in AMP URLs.

If the same issue occurs in transitional mode please share your full PHP error log via an publicly accessible Google doc, a GIST or PasteBin. You can provide a link to this error log using the same form used previously.

Interesting.. so I am wondering if the links just changed?
When I go to https://frugalflyer.ca/blog/compilation-of-us-to-canada-mail-forwarders/?amp it works. The link always used to be /amp.

Is this normal?

Great to hear that it’s working. Did you switch modes at any stage, or even apply mobile redirection? There are different conditions that can result in differing AMP endpoints. If you were navigating to your AMP URLs manually by appending the endpoint maybe the issue was the endpoint was modified. I find the AMP Validator Chrome extension to be very useful for checking your AMP URLs, without having to search for the amphref link each time.

Note that you can soon choose your preferred AMP endpoint, with more details in this support topic.

Have you also tested out your themes AMP compatibility plugin, as opposed to using the plugin in reader mode? You may prefer transitional mode to ensure visual parity.

If you look at the source code of https://frugalflyer.ca/blog/compilation-of-us-to-canada-mail-forwarders/ you’ll find:

<link rel="amphtml" href="https://frugalflyer.ca/blog/compilation-of-us-to-canada-mail-forwarders/amp/">

So it is currently using /amp/ and it is working.

Note that if you switch from AMP Legacy to another Reader theme then the paired URL structure changes from /amp/ to ?amp. This will no longer be the case as of v2.1 which will allow you to select a paired URL structure regardless of the mode or selected theme. The aforementioned support topic has more details.