CAPTCHA cache issue

Do you have this line in your wp-config.php file?

define('WP_CACHE', TRUE);

I just checked 11 wp-config.

Two which are dormant/test sites have the line you requested.

<?php
define('WP_CACHE', TRUE);

The other 9 which are the up-to-date sites do not have the line you requested.

Please advise if I need to add it in manually to all the wp-config files?

Normally ZenCache should have added it. Ask ZenCache author for support.

Adding in

<?php
define('WP_CACHE', TRUE);

as the second line of the wp-config does not solve the caching of the CAPTCHA image on page refresh

I might have a fix on this. I think this might be a FireFox issue.

See below
I have enabled ZenCache on BajanThings. (BTW define(‘WP_CACHE’, TRUE); is added in on line 2 of wp-config.php once you enable ZenCache… if you disable it removes line 2)

Go to: https://www.bajanthings.com/contact-burts/

* Open it in IE, I am using Version 11.0.9600.17842,
press page reload and the CAPTCHA image refreshes as expected.

* Open it in Chrome, I am using Version 43.0.2357.132 m,
press page reload and the CAPTCHA image refreshes as expected.

* Open it in Firefox, I am using Version 39.0,
press page reload and the CAPTCHA image DOES NOT refreshes as expected. Are you seeing this too?

What other plugins do you use?

Installed plugin on BajanThings are:
Akismet
Contact Form 7
Easy Theme and Plugin Upgrades
FooBox HTML & Media Lightbox
Google Analyticator
Google XML Sitemaps
Jetpack by WordPress.com
NextGEN Gallery by Photocrati
NextGEN Plus by Photocrati
Really Simple CAPTCHA
SEO Ultimate
Simple Breaks
Subscribe2
TablePress
Weaver Show Posts
Weaver Themes Shortcode Compatibility
Weaver Xtreme Plus
Weaver Xtreme Theme Support
WP-DBManager
WP-Optimize
ZenCache

Feedback from ZenCache after post about Firefox.

@raamdev I see nothing ZenCache-specific here. This really seems to be two issues with CF7.

Not setting DONOTCACHEPAGE on AJAX responses that deliver dynamic content.
Not calling nocache_headers() on AJAX responses that deliver dynamic content.

Those are both educated guesses. I have not spent enough time with that plugin to say absolutely for sure. Further investigation on their part would be suggested.

For what its worth I am using a win8.1 64 bit

No, they are not the direct cause of this issue. Maybe ZenCache isn’t related, either.

This is the HTML of the CAPTCHA image. I got this with the latest Firefox and Firebug.

<img class="wpcf7-form-control wpcf7-captchac wpcf7-captcha-captcha-603" width="84" height="28" src="https://www.bajanthings.com/wp-content/uploads/wpcf7_captcha/1247228803.png" alt="captcha" srcset="https://i0.wp.com/www.bajanthings.com/wp-content/uploads/wpcf7_captcha/1310244177.png?zoom=2&resize=84%2C28" src-orig="https://i0.wp.com/www.bajanthings.com/wp-content/uploads/wpcf7_captcha/1310244177.png?resize=84%2C28" scale="2">

The “srcset”, “src-orig”, and “scale” attributes are not by Contact Form 7, they are actually added by something unknown. Something is changing the output of Contact Form 7.

The “src” attribute is updated correctly by Contact Form 7, but “srcset” and “src-orig” are not. This is the direct cause of your issue.

You need to trace who is adding those problematic attributes. Try deactivating all other plugins and switching to the default theme. If this fixes the issue, then reactivate them one by one.

Initially I thought it was Foobox….

Those parameters that you are referring to are added by the WP Jetpack Photon caching tool where WP caches your images and serve them from their super-fast network.

This is the CAPTCHA image with WP Jetpack Photon deactivated:

<img class="wpcf7-form-control wpcf7-captchac wpcf7-captcha-captcha-603" width="84" height="28" src="https://www.bajanthings.com/wp-content/uploads/wpcf7_captcha/1662277107.png" alt="captcha" scale="0">

The WP Photon issue now makes sense now. I run another site that also uses your contact tool.
https://www.art-treasures-gallery.com/contact-art-treasures-gallery/

I was struggling to work out why that contact form appeared to work and why all the others CAPTCHA images on my other sites were caching.

For Art Treasures Gallery I turned off Photon as the WP authors have been outspoken about free speech in China and China has hit back by blocking anything associated with WP servers, so to have the images on the Art Treasures Gallery website visible in China I had to uncouple all the tools that are linked to WP servers. For more info you can read about it here: https://www.art-treasures-gallery.com/website/

What’s the next step?

@takayuki Miyoshi just checking in to see where we go from here given issue appears to be WP Jetpack Photon

Jetpack’s support?

@takayuki Miyoshi this has been an issue for a while now for me and other. Think its time to move on and swap out to Fast Secure Contact Form which I’ve been testing and works out of the box with Jetpack et al.