To fix this issue you have to Increase WordPress Memory Limit.
The most common cause of this error is the lack of memory available for WordPress to use. To fix this, you need to increase the amount of memory PHP can use on your server.
You can do this by adding the following code to your wp-config.php file.
define( 'WP_MEMORY_LIMIT', '256M' );
This code increases the WordPress memory limit to 256MB, which would be enough to fix any memory limit issues.
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Next Option you can Try | Using The .htaccess Method
This method allows you to control how Imagick uses server resources. Many shared hosting providers limit Imagick’s ability to use multiple threads for faster image processing. However, this would result in you seeing the HTTP error when uploading images.
An easy fix is to add the following code in your .htaccess file:
SetEnv MAGICK_THREAD_LIMIT 1
This code simply limits Imagick to use a single thread to process images.
More Clarification you follow info from wpbeginner.com