As a matter of fact, fighting with Web Contentn Accessibility Guidelines (aka WCAG 2.0) can give you hard times. It's quite impossible to meet every single one specific guidline without using an appropriate Web Accessibility Checker.
One of the best is achecker.ca. At least, here in Greece, it is the most common Web Accessibility Checker for all kind of checks; caring webpage owners, simple curious users, young programmers, experienced developers, even the authorities use it so they're sure your website is compliant with WCAG.
Of course, nothing in life is perfect. Achecker.ca can sometimes be tricky - in contrast to Wave Validator, which is a more powerful and solid tool, although less people use it as far as I know.
I know you came here for the title, but it's a blog post here, so, I can say at least a few words as a prologue! If this post helps you, I guess you will forget it the very next moment! But it really worked for me to let off today's steam!
Anyway, let's cut to the chase:
Achecker sometimes crashes and causes "internal server error", leading to an empty blank page.
Guys there, hm, they aren't always helpful (I sent an e-mail but....) and their forum isn't always responsive.
I guess that this was your google search that brought you here. So, let me guess:
Your website is built on Wordpress
It's "Slider Rebolution Responsive Wordpress Plugin"
If this is so, I've got good and bad news. Good news? You now know that this specific wordpress plugin is causing this to Achecker. Bad News? I can't give you any advice how to fix the plugin (if there is a problem there) or the achecker. Now I reconsider, yes I can: You can either change your plugin or your checker :P
I guess you don't or cant, so this is my advice about how to go on: First of all ...disable the plugin! (Don't delete it. Just disable it for a few minutes / hours)
Now you can use achecker so that you can see all problems caused by poor WCAG adjustment.
Work out all these problems, using the checker at the same time to see your progress. Don't forget to clear caches after disabling the plugin, ok?
Once you solved all those issues - by the way, in my experience, achecker.ca locates more errors and problems than Wave Validator- you have a WCAG compliant web site. Is that enough for you, as long as you can't have a fully functional website and it's checker working at the same time? I can't tell, that's your decision. In my opinion, as long as you have an Achecker.ca and Wave Validator pass at the same time, plugin - checker conflict is none of my business and my website is fine. I'd like to know your way of thinking, you can post a comment below.
What about "hmm man, I don't even use this plugin"? At least I tried, you can give me that!
Anyway, you know the process now. I didn't have any problem like this using other CMS such as Drupal or Joomla. So as far as I'm concerned, it's narrowed down to Wordpress. I found my mischievous plugin by trial and error -four of my wordpress websites didn't work on achecker, other wordpress sites worked fine, every other site worked fine too. If you do it carefully, it doesn't take too long. Don't forget to clear caches after each enable/disable click, or you'll get confused about the plugin that causes the problem.
In case you're bored to do it, you can give me a try - let us adjust your page and make it full comformant with WCAG 2.0.
We do not restrict ourselves to error correction. We have Eucleides!
Have a look at our demo, by the way, you may find it useful!