Getting this error. Please can anyone help us ?

1 exception(s): Exception #0 (Magento\Framework\Config\Dom\ValidationException): Element 'block', attribute 'class': [facet 'pattern'] The value 'Ortho\Theme\Block\category\Leftcategory' is not accepted by the pattern '[A-Z][a-zA-Z\d](\[A-Z][a-zA-Z\d])*'. Line: 798

Element 'block', attribute 'class': 'Ortho\Theme\Block\category\Leftcategory' is not a valid value of the atomic type 'blockClassType'. Line: 798

5 Answers 5


Seems that this is happening because of the block class path, where the 'category' folder is written with lower case. Try to change it to 'Category'.

  • Maybe but i just can not figure it out where i should change. Any idea?
    – user38833
    Oct 25, 2017 at 10:16

Please share the full error stack.

This error discussed here: https://github.com/magento/magento2/issues/11110

My take away is that the validation is effective in M 2.2, not prior. One issue mentioned in that post is that Leading slashes in class references in Templates. E.g. /myspecialclass.../../ is not allowed, shile myspecialclass.../../ is allowed.

  • This can be, but i can not figure it out where and in which file i should changed. Please can you tel me where exactly i have to be
    – user38833
    Oct 25, 2017 at 10:15

In my case, there I used Magefan of blog extension in view page error.

It's resolved by below changes.

<block class="\Magento\Framework\View\Element\Text\ListText" name="blog.post.bottom">

I has changed it to:

<block class="Magento\Framework\View\Element\Text\ListText" name="blog.post.bottom">

One of your Module's Block class probably named Ortho\Theme\Block\Category\Leftcategory

Try to search all your layout.xml files in your app/code or app/design for this string and change it according to the actual class namespace

(as Nicolas mentioned, it's probably should be Ortho\Theme\Block\Category\Leftcategory with a capital C)


You need to change the file name local.xml.sample to local.xml in folder pub/errors

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