captcha plugin for Participants Database HTTP Error 500

I’m sorry, I really have no idea what’s going on there. I haven’t been able to duplicate the issue here, and without some kind of indication what the error is, all I can think of is that the validation request back to Google for the recaptcha is getting blocked by a security rule on your server.

Does it work OK if you use the built-in math captcha?

I’ve checked my firewall config and there is nothing restrictive there.
I have implemented the built in math captcha and I get the same result.

I submit the answer and then there is a few second wait and then a timeout and HTTP 500 error with nothing hitting the logs

So I have changed the logging level on httpd and now get the following

Error

[Thu Jul 27 10:30:02 2017] [debug] mod_deflate.c(687): [client x.x.x.x] Zlib: Compressed 63593 to 20178 : URL /index.php
[Thu Jul 27 10:30:03 2017] [debug] mod_deflate.c(687): [client x.x.x.x] Zlib: Compressed 0 to 2 : URL /index.php, referer: https://site.com/
[Thu Jul 27 10:30:24 2017] [debug] mod_deflate.c(687): [client x.x.x.x] Zlib: Compressed 63760 to 20260 : URL /index.php, referer: https://site.com/
[Thu Jul 27 10:30:24 2017] [debug] mod_deflate.c(687): [client x.x.x.x] Zlib: Compressed 0 to 2 : URL /index.php, referer: https://site.com/
[Thu Jul 27 10:30:34 2017] [debug] mod_deflate.c(687): [client x.x.x.x] Zlib: Compressed 47 to 49 : URL /wp-admin/admin-ajax.php, referer: https://site.com/wp-admin/admin.php?page=participants-database-manage_fields
[Thu Jul 27 10:30:48 2017] [debug] mod_deflate.c(687): [client x.x.x.x] Zlib: Compressed 63764 to 20258 : URL /index.php, referer: https://site.com/
[Thu Jul 27 10:30:48 2017] [debug] mod_deflate.c(687): [client x.x.x.x] Zlib: Compressed 0 to 2 : URL /index.php, referer: https://site.com/
[Thu Jul 27 10:31:08 2017] [debug] mod_deflate.c(687): [client x.x.x.x] Zlib: Compressed 63761 to 20257 : URL /index.php, referer: https://site.com/
[Thu Jul 27 10:31:08 2017] [debug] mod_deflate.c(687): [client x.x.x.x] Zlib: Compressed 0 to 2 : URL /index.php, referer: https://site.com/
[Thu Jul 27 10:31:25 2017] [debug] mod_deflate.c(687): [client x.x.x.x] Zlib: Compressed 0 to 2 : URL /index.php, referer: https://site.com/

Access

x.x.x.x - - [27/Jul/2017:10:36:14 +0100] "GET / HTTP/1.1" 200 20195 "-" "Mozilla/5.0 (Windows NT 6.1; WOW64; Trident/7.0; rv:11.0) like Gecko"
x.x.x.x - - [27/Jul/2017:10:36:27 +0100] "GET /?dm=4b898bea6ebcb95a7966fbf94c19186a&action=load&blogid=18&siteid=1&t=1776983260&back=http%3A%2F%2Fsite.com%2F HTTP/1.1" 200 20 "https://site.com/" "Mozilla/5.0 (Windows NT 6.1; WOW64; Trident/7.0; rv:11.0) like Gecko"
172.16.10.91 - - [27/Jul/2017:10:36:27 +0100] "POST /wp-cron.php?doing_wp_cron=1501148187.2899420261383056640625 HTTP/1.1" 200 20 "https://mainsite.com/wp-cron.php?doing_wp_cron=1501148187.2899420261383056640625" "WordPress/4.8; https://mainsite.com"
x.x.x.x - - [27/Jul/2017:10:36:49 +0100] "POST / HTTP/1.1" 500 20 "https://site.com/" "Mozilla/5.0 (Windows NT 6.1; WOW64; Trident/7.0; rv:11.0) like Gecko"
x.x.x.x - - [27/Jul/2017:10:37:30 +0100] "-" 408 - "-" "-"

Changing the size of the screen also looks like it makes a difference

• This reply was modified 7 years, 7 months ago by londonnet.

OK I get the same result if I use the internal math captcha and nothing in the logs.

However If I change the window size The captcha functions more normally although unless my maths is shocking it is unable to read a correct answer and move on, it keeps asking for a new maths question. Go back to full size and we get a time out and http 500

Well, there’s new information, although I’m not sure I know what it tells us.

The math captcha won’t validate unless the recapcha plugin is deactivated…that bug I have a fix for.

The window size suggests the server is handling responsive displays…is that possible? That would be unusual I think.

Yes if I disable the recapcha plugin the built in math capcha works just fine on any screen size.

So the clue here must be that there is an issue perhaps with the theme I am using and the recapcha plugin???

I’ll try another theme and see if that makes a diference

and we also know it’s definitely in the recaptcha code…that’s helpful.

I just released an update to the recaptcha add-on. It checks to make sure it can perform the verification before it tries it. That will probably solve the 500, but it won’t allow the recaptcha to validate because that means that for one reason or another, the validation request to Google can’t be made.

• This reply was modified 7 years, 7 months ago by xnau webdesign. Reason: spelling

OK, so I have found the issue. I have a firewall rule which is blocking traffic to and from a set of subnets out on the internet who were attempting to gain access ect. It looks like the plugin (Google) maybe trying to connect to something in that subnet.

I’m not surprised, the subnets I am blocking are pretty big.

Do you know what the plugin is trying to connect to?

Thanks for your support. The last bit of information helped me to find what I was looking for. If it’s easy perhaps the plugin can generate an error message to say it is unable to connect to resource it needs.

Regards

The actual request is handled by the WP_Http class, and I do dump the error message to the log if it fails to connect…but if your firewall is throwing a 500 then nothing else can happen after that.

The plugin uses the standard Google URL to verify the user’s input:

https://www.google.com/recaptcha/api/siteverify

Thanks for the link. I’ll take a look and see what I am blocking.

Just so I know for sure. Which log file does the plugin write to?

Thanks again for your help