Invalid ID error when saving or previewing a new form

In some cases, the system may throw an Invalid ID: Please check the codeĀ error when previewing a new/existing form from the builder. If you are facing this, then it is likely to be for the following reasons.

#1: Empty Line Output

Some plugin, or your theme is printing empty line on PHP output. This is invaliding all ajax responses and therefore the system can not work properly.

To identify the culprit please follow the procedure below:

  1. Deactivate all other plugins (except eForm).
  2. Switch to a default theme.
  3. Activate plugins one by one until the issue reappears.
    1. When it reappears, you’d find the causing plugin.
  4. If activating all plugins does not bring back the issue, then activate your them and it should.

Once you have identified the causing plugin/theme, please contact with their author to get it solved. Ask them to remove any empty line print inside one (or more) of the PHP files.

#2: PHP Warning generated by exceeding POST variable

In some cases, if you are creating a rather large form the PHP may print error output like,

Warning: parse_str(): Input variables exceeded 1000. To increase the limit change max_input_vars in php.ini.

To solve this, you’d need to increase PHP Post variable limit as mentioned here.

#3: Other PHP Notice

Under some rare scenario, PHP may output some notice which will be printed along with AJAX output and which will break the form preview. To rectify this, disable PHP error output.

Swashata has written 257 articles

Hi there, I am the Lead Developer at I love to create something beautiful for WordPress and here I write about how to use them. When I am not working, usually I am doing a number of other creative things ;).