Fixed: There has been a critical error on this website | WordPress Blog

The error message you're receiving, "There has been a critical error on this website," is a common WordPress issue often related to one of the following causes:

1. Plugin Conflict: One of your active plugins (related to the blog or “read more” functionality) may be conflicting with WordPress core or another plugin. Try disabling all plugins and re-enabling them one by one to identify the culprit.

2. Theme Issues: If you're using a custom or third-party theme, a recent update or a conflict in the theme files (especially in the single post page template) might cause the blog's "Read More" functionality to break. Try switching to a default theme like "Twenty Twenty-One" to see if the issue persists.

3. PHP Errors: This error could be caused by a PHP error, particularly if a blog article's template file (single.php or content.php) has invalid code. Enable WordPress debugging to identify the exact cause by adding the following lines in your wp-config.php file:

   define( 'WP_DEBUG', true );
   define( 'WP_DEBUG_LOG', true );
   define( 'WP_DEBUG_DISPLAY', false );
   

4. Memory Limit Exhaustion: If your server runs out of allocated memory, it might cause errors when trying to load the blog posts. You can increase the memory limit by adding this to wp-config.php:

   define( 'WP_MEMORY_LIMIT', '256M' );

5. Permalink Issues: The problem might also be related to broken permalinks. Go to Settings > Permalinks and click Save to reset the permalinks without making any changes.

6. Database Issues: A corruption in the database might be causing the blog articles to malfunction. Running a repair on your database from phpMyAdmin or using a plugin to optimize and repair your database may help resolve the issue.

After diagnosing the error using these steps, you should be able to identify what is causing the issue with your blog's "Read More" functionality. If not, reviewing the error logs or consulting with your hosting provider might offer more insight. 

I was able to sort my site after I increased memory limit to 512M and disabled 2 plugins that were causing the conflict.