Easily fix WordPress POST and REQUEST 404 error on form submission

If you have been trying to submit a form in WordPress and you are receiving a 404 error page, well the chances of the cause being using a reserved keyword can be extremely high. This is because one or many of your field name is being reserved by WordPress.

In the below snippet, name=”calendar” is a reserved word. Submitting the form will display the bad 404 page. In-order to avoid we can prefix it name=”mytheme_calendar” or ensure that the variables we use are not reserved by WordPress?

<form action="<?php the_permalink();?>" method="post">
        <label>Calendar</label>
        <input type="text" name="calendar"/>
    <input type="submit" value="Submit" name="qwe" value="submit" />
</form>

What do you mean “Reserved by WordPress” and “What are the keywords being reserved” ?

The following keywords or terms are being used by WordPress for important operations as a result, WordPress prevents you from using them. If you have been following WordPress best practices, you wouldn’t encounter an issue as it is a good practice to prefix every variable with a unique prefix word. This not only avoids conflict with WordPress but with other plugins and themes

  • attachment
  • attachment_id
  • author
  • author_name
  • calendar
  • cat
  • category
  • category__and
  • category__in
  • category__not_in
  • category_name
  • comments_per_page
  • comments_popup
  • custom
  • customize_messenger_channel
  • customized
  • cpage
  • day
  • debug
  • embed
  • error
  • exact
  • feed
  • hour
  • link_category
  • m
  • minute
  • monthnum
  • more
  • name
  • nav_menu
  • nonce
  • nopaging
  • offset
  • order
  • orderby
  • p
  • page
  • page_id
  • paged
  • pagename
  • pb
  • perm
  • post
  • post__in
  • post__not_in
  • post_format
  • post_mime_type
  • post_status
  • post_tag
  • post_type
  • posts
  • posts_per_archive_page
  • posts_per_page
  • preview
  • robots
  • s
  • search
  • second
  • sentence
  • showposts
  • static
  • subpost
  • subpost_id
  • tag
  • tag__and
  • tag__in
  • tag__not_in
  • tag_id
  • tag_slug__and
  • tag_slug__in
  • taxonomy
  • tb
  • term
  • terms
  • theme
  • title
  • type
  • w
  • withcomments
  • withoutcomments
  • year

If you think that this is not causing the issue, leave a comment and will help you out. WordPress is an interesting CMS and while developing themes and plugins you might come across several issues. We always recommend reading WordPress guide. It covers guides for both Beginners and Intermediates