Title: Error 501 on activation
Last modified: August 22, 2016

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# Error 501 on activation

 *  Resolved [Marcelo Pedra](https://wordpress.org/support/users/kent-brockman/)
 * (@kent-brockman)
 * [11 years, 4 months ago](https://wordpress.org/support/topic/error-501-on-activation/)
 * Hi! I just wanted to give it a try to your plugin but this happens anytime I 
   try to activate the plugin:
 * > Error 501 – Not Implemented
   > GET to /staging/wp-admin/plugins.php not supported.
   >  Additionally, a 404 Not
   > Found error was encountered while trying to use an ErrorDocument to handle 
   > the request.
 * FYI: the server runs PHP 5.4.35 as cgi. Apache 2.4. MySQL 5.6.
    Any ideas? Let
   me know if you need more info.
 * [https://wordpress.org/plugins/mail-on-update/](https://wordpress.org/plugins/mail-on-update/)

Viewing 9 replies - 1 through 9 (of 9 total)

 *  Plugin Author [foobar2022](https://wordpress.org/support/users/kubi23/)
 * (@kubi23)
 * [11 years, 4 months ago](https://wordpress.org/support/topic/error-501-on-activation/#post-5689716)
 * This doesnt look like a plugin issue. 501 is a server issue. Does this only occur
   with the mail-on-update plugin?
 *  Thread Starter [Marcelo Pedra](https://wordpress.org/support/users/kent-brockman/)
 * (@kent-brockman)
 * [11 years, 4 months ago](https://wordpress.org/support/topic/error-501-on-activation/#post-5689718)
 * Yep, I have almost 40 WP sites and multisites in that server since 2010 and this
   is the first time I see this error.
    Any idea? maybe the server firewall?
 *  Thread Starter [Marcelo Pedra](https://wordpress.org/support/users/kent-brockman/)
 * (@kent-brockman)
 * [11 years, 4 months ago](https://wordpress.org/support/topic/error-501-on-activation/#post-5689720)
 * No PHP errors indeed. I’ll test it in other sites, and in other servers.
 *  Plugin Author [foobar2022](https://wordpress.org/support/users/kubi23/)
 * (@kubi23)
 * [11 years, 4 months ago](https://wordpress.org/support/topic/error-501-on-activation/#post-5689722)
 * Is it a multisite installation you are installing the plugin? When does the error
   exactly occur?
 * Cheers,
    Sven
 *  Thread Starter [Marcelo Pedra](https://wordpress.org/support/users/kent-brockman/)
 * (@kent-brockman)
 * [11 years, 4 months ago](https://wordpress.org/support/topic/error-501-on-activation/#post-5689723)
 * I tested it on PHP 5.3: it works ok. Not received an update notification but 
   the plugin was able to be active and work.
 * But under PHP 5.4.35 is not possible to activate the plugin. It generates a 501,
   and 404s when you try to uninstall it. Manually deleted now.
 * Both servers are equally configured.
 *  Thread Starter [Marcelo Pedra](https://wordpress.org/support/users/kent-brockman/)
 * (@kent-brockman)
 * [11 years, 4 months ago](https://wordpress.org/support/topic/error-501-on-activation/#post-5689724)
 * Not in multisite yet. I tested it in 2 standalone WP on PHP 5.3.29, and 2 other
   sites using PHP 5.4.35
 *  Plugin Author [foobar2022](https://wordpress.org/support/users/kubi23/)
 * (@kubi23)
 * [11 years, 4 months ago](https://wordpress.org/support/topic/error-501-on-activation/#post-5689725)
 * Is it a multisite installation you are installing the plugin?
 *  Thread Starter [Marcelo Pedra](https://wordpress.org/support/users/kent-brockman/)
 * (@kent-brockman)
 * [11 years, 4 months ago](https://wordpress.org/support/topic/error-501-on-activation/#post-5689726)
 * As I said above: not in multisite yet. I just want to make it work in standalones
   first.
 *  Plugin Author [foobar2022](https://wordpress.org/support/users/kubi23/)
 * (@kubi23)
 * [11 years, 4 months ago](https://wordpress.org/support/topic/error-501-on-activation/#post-5689892)
 * To be honest, I have no idea how to dig into this issue. I will check if there
   are any deprecated function which may collide with the PHP version.

Viewing 9 replies - 1 through 9 (of 9 total)

The topic ‘Error 501 on activation’ is closed to new replies.

 * ![](https://s.w.org/plugins/geopattern-icon/mail-on-update_efefef.svg)
 * [Mail On Update](https://wordpress.org/plugins/mail-on-update/)
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 * [Reviews](https://wordpress.org/support/plugin/mail-on-update/reviews/)

 * 9 replies
 * 2 participants
 * Last reply from: [foobar2022](https://wordpress.org/support/users/kubi23/)
 * Last activity: [11 years, 4 months ago](https://wordpress.org/support/topic/error-501-on-activation/#post-5689892)
 * Status: resolved