Title: PHP error: Undefined array key “HTTP_USER_AGENT” Last modified: December 6, 2021 --- # PHP error: Undefined array key “HTTP_USER_AGENT” * Resolved [dcbuffalo](https://wordpress.org/support/users/dcbuffalo/) * (@dcbuffalo) * [4 years, 5 months ago](https://wordpress.org/support/topic/php-error-undefined-array-key-http_user_agent/) * I’m getting the following error consistently in our php error logs, a number of times per day – anywhere from just a couple times a day to as much as 50 as far as I can tell: * PHP Warning: Undefined array key “HTTP_USER_AGENT” in /home/xxxxxxxx/public_html/ wp-content/plugins/mad-mimi-wp/includes/classes/RobotDetector/RobotDetector.php on line 307 * I’m not sure what is triggering it. Can anyone offer any insight into the cause of this error, and a solution? * Thanks, David * The page I need help with: _[[log in](https://login.wordpress.org/?redirect_to=https%3A%2F%2Fwordpress.org%2Fsupport%2Ftopic%2Fphp-error-undefined-array-key-http_user_agent%2F%3Foutput_format%3Dmd&locale=en_US) to see the link]_ Viewing 12 replies - 1 through 12 (of 12 total) * Plugin Support [gavinohanlon](https://wordpress.org/support/users/gavinohanlon/) * (@gavinohanlon) * [4 years, 5 months ago](https://wordpress.org/support/topic/php-error-undefined-array-key-http_user_agent/#post-15141557) * Hi Dcbuffalo, * Thanks for reaching out to us. * Are your optin forms working ? * With regard to the error message, we will look to get that fixed on the next version release. * Thank you again for reporting it. * All the best. * Thread Starter [dcbuffalo](https://wordpress.org/support/users/dcbuffalo/) * (@dcbuffalo) * [4 years, 5 months ago](https://wordpress.org/support/topic/php-error-undefined-array-key-http_user_agent/#post-15141667) * It has been tested before and it worked. I will get confirmation of recent sign- ups and let you know. * Thanks for looking into it! * Thread Starter [dcbuffalo](https://wordpress.org/support/users/dcbuffalo/) * (@dcbuffalo) * [4 years, 5 months ago](https://wordpress.org/support/topic/php-error-undefined-array-key-http_user_agent/#post-15143851) * It is actually not working. If you enter a valid email address and click the submit button, the button says “Failed to add user – 401”. * Plugin Support [gavinohanlon](https://wordpress.org/support/users/gavinohanlon/) * (@gavinohanlon) * [4 years, 5 months ago](https://wordpress.org/support/topic/php-error-undefined-array-key-http_user_agent/#post-15143904) * Hi Dcbuffalo, * Thanks for getting back to me. * Sometimes, the API keys can go stale after a while. We would recommend going in and getting a new API key to try and clear all your cache from both the browser and server if you are using any caching plugins. * You could also check that you don’t have any conflicting plugins doing a similar action. Like another optin form plugin that is using MadMimi on your site. You would turn those other plugins off and see if the form then works. * Feel free to get back to us if there is anything else. * All the best. * Thread Starter [dcbuffalo](https://wordpress.org/support/users/dcbuffalo/) * (@dcbuffalo) * [4 years, 5 months ago](https://wordpress.org/support/topic/php-error-undefined-array-key-http_user_agent/#post-15143917) * I just discovered that the email address for the Mad Mimi account had been updated but I wasn’t aware. However, even after updating that, I still get an error that now reads “Failed to add user – 400”. * Plugin Support [gavinohanlon](https://wordpress.org/support/users/gavinohanlon/) * (@gavinohanlon) * [4 years, 5 months ago](https://wordpress.org/support/topic/php-error-undefined-array-key-http_user_agent/#post-15143936) * Hi again, * I tried the optin form at the bottom of your main page. This time the email was accepted. It did not show a similar error message as before. * The email I tested with ended with [1234@gmail.com](https://wordpress.org/support/topic/php-error-undefined-array-key-http_user_agent/1234@gmail.com?output_format=md) * If you are testing the form, just make sure you are using an email address that is different to one that might already be in your list. * Feel free to get back to us if there is anything else. * All the best. * Thread Starter [dcbuffalo](https://wordpress.org/support/users/dcbuffalo/) * (@dcbuffalo) * [4 years, 5 months ago](https://wordpress.org/support/topic/php-error-undefined-array-key-http_user_agent/#post-15143943) * I refreshed the API key and set the list appropriately. It now works perfectly again – thanks! * Plugin Support [gavinohanlon](https://wordpress.org/support/users/gavinohanlon/) * (@gavinohanlon) * [4 years, 5 months ago](https://wordpress.org/support/topic/php-error-undefined-array-key-http_user_agent/#post-15143965) * Hi there, * That’s good to hear. Happy to hear you got it working now. * Feel free to get back to us if there is anything else. * All the best. * Thread Starter [dcbuffalo](https://wordpress.org/support/users/dcbuffalo/) * (@dcbuffalo) * [4 years, 3 months ago](https://wordpress.org/support/topic/php-error-undefined-array-key-http_user_agent/#post-15382618) * So the same php error is still occurring. I refreshed the API key, and now the interface doesn’t allow me to set a list for the optin form, which seems problematic. Any thoughts? * Thread Starter [dcbuffalo](https://wordpress.org/support/users/dcbuffalo/) * (@dcbuffalo) * [4 years, 3 months ago](https://wordpress.org/support/topic/php-error-undefined-array-key-http_user_agent/#post-15382634) * Also FYI – the error started back up on December 9, pretty much after I cleared out the error log, and it’s logged almost every day since, usually several times. * Thread Starter [dcbuffalo](https://wordpress.org/support/users/dcbuffalo/) * (@dcbuffalo) * [4 years, 3 months ago](https://wordpress.org/support/topic/php-error-undefined-array-key-http_user_agent/#post-15382639) * I don’t believe it’s sending the confirmation email properly, but that’s probably an SMTP issue I’m working on separately. * Plugin Support [gavinohanlon](https://wordpress.org/support/users/gavinohanlon/) * (@gavinohanlon) * [4 years, 3 months ago](https://wordpress.org/support/topic/php-error-undefined-array-key-http_user_agent/#post-15393672) * Hi Dcbuffalo, * Thanks for your patience with this. * Is it the same error message as before ? This one – PHP Warning: Undefined array key “HTTP_USER_AGENT” in /home/xxxxxxxx/public_html/wp-content/plugins/mad-mimi- wp/includes/classes/RobotDetector/RobotDetector.php on line 307 * We are trying to track down what is causing the API key not to be accepted with Mad Mimi. The developer is looking into the issue now to diagnose it. * If I hear anything back about fixing it, I will certainly reach out to you again. * In the meantime, don’t hesitate to let us know if there is anything else. * All the best. Viewing 12 replies - 1 through 12 (of 12 total) The topic ‘PHP error: Undefined array key “HTTP_USER_AGENT”’ is closed to new replies. * ![](https://s.w.org/plugins/geopattern-icon/mad-mimi-wp_f7f7f7.svg) * [Mad Mimi Forms by Optin Cat](https://wordpress.org/plugins/mad-mimi-wp/) * [Frequently Asked Questions](https://wordpress.org/plugins/mad-mimi-wp/#faq) * [Support Threads](https://wordpress.org/support/plugin/mad-mimi-wp/) * [Active Topics](https://wordpress.org/support/plugin/mad-mimi-wp/active/) * [Unresolved Topics](https://wordpress.org/support/plugin/mad-mimi-wp/unresolved/) * [Reviews](https://wordpress.org/support/plugin/mad-mimi-wp/reviews/) * 12 replies * 2 participants * Last reply from: [gavinohanlon](https://wordpress.org/support/users/gavinohanlon/) * Last activity: [4 years, 3 months ago](https://wordpress.org/support/topic/php-error-undefined-array-key-http_user_agent/#post-15393672) * Status: resolved