Title: Sync error Last modified: August 21, 2016 --- # Sync error * Resolved [JanJanssen00](https://wordpress.org/support/users/janjanssen00/) * (@janjanssen00) * [12 years, 2 months ago](https://wordpress.org/support/topic/sync-error/) * Hi there, * Great plugin (already used it on another website) but is not working on a new website I’m setting up. 100% sure both API and List ID are correct, but getting the following error all the time: * Campaign Monitor synchronization error. Must supply a valid HTTP Basic Authorization header * Any clue what’s going wrong? * Thanks, Jan. * [https://wordpress.org/plugins/campaign-monitor-synchronization/](https://wordpress.org/plugins/campaign-monitor-synchronization/) Viewing 11 replies - 1 through 11 (of 11 total) * Plugin Author [Carlo Roosen](https://wordpress.org/support/users/carloroosen/) * (@carloroosen) * [12 years, 2 months ago](https://wordpress.org/support/topic/sync-error/#post-4758403) * No clue at all. I would say there is a mistake in your API key and list ID :D. I would be happy to help you further, but I dont know where to start. * What is different in this setting compared to the website where you use it successfully? Is it the same hosting environment? Are there other plugins active? It seems the only way to go is to eliminate possible causes one by one. * Good luck, Carlo * Plugin Author [Carlo Roosen](https://wordpress.org/support/users/carloroosen/) * (@carloroosen) * [12 years, 1 month ago](https://wordpress.org/support/topic/sync-error/#post-4758450) * Is the problem solved in the meantime? I would be happy to help you but I need a bit more information. * Cheers, Carlo * Thread Starter [JanJanssen00](https://wordpress.org/support/users/janjanssen00/) * (@janjanssen00) * [12 years, 1 month ago](https://wordpress.org/support/topic/sync-error/#post-4758464) * Nope, problem still remains. Double checked API key and list ID, so problem can’t be that. * Please let me know what kind of info you need to help me, very grateful for that! * Plugin Author [Carlo Roosen](https://wordpress.org/support/users/carloroosen/) * (@carloroosen) * [12 years, 1 month ago](https://wordpress.org/support/topic/sync-error/#post-4758465) * Hi, The easiest way: give me access to your website (wordpress admin and ftp). Please contact me via email, mail[at]carloroosen[dot]nl. * Plugin Author [Carlo Roosen](https://wordpress.org/support/users/carloroosen/) * (@carloroosen) * [12 years, 1 month ago](https://wordpress.org/support/topic/sync-error/#post-4758469) * Hi Jan, Do you still need any help? Please contact me by email. * Carlo * [jarzabjacek](https://wordpress.org/support/users/jarzabjacek/) * (@jarzabjacek) * [12 years, 1 month ago](https://wordpress.org/support/topic/sync-error/#post-4758473) * Hi, first, thanks for plugin. Just install it on clients wordpress 3.8.1 and it gives the same error whenever I try to ‘Save and Sync’: _Campaign Monitor synchronization error. Must supply a valid HTTP Basic Authorization header Would appreciate your help. * thanks Jacek * Plugin Author [Carlo Roosen](https://wordpress.org/support/users/carloroosen/) * (@carloroosen) * [12 years, 1 month ago](https://wordpress.org/support/topic/sync-error/#post-4758474) * Hi Jacek, * We are still working on this issue. If you want me to have a look at your website, please contact me via email. * Just to be sure, are you using the correct List ID and API key? Both are a 32 character hexadecimal string. * Good luck, Carlo * [jarzabjacek](https://wordpress.org/support/users/jarzabjacek/) * (@jarzabjacek) * [12 years, 1 month ago](https://wordpress.org/support/topic/sync-error/#post-4758475) * Hi Carlo, thanks for quick reply… yes we are 100% positive sure we are using correct AccountApi key API Subscriber List ID * I just discover it conflicts with another plugin we use for subscription forms: [http://wordpress.org/plugins/ajax-campaign-monitor-forms/](http://wordpress.org/plugins/ajax-campaign-monitor-forms/) * When i disable it your sync went through and works fine now! While syncing existing members is far more way important for us than signing in normal subscribers I will leave your plugin on and ask developers of this AjaxForms plugin for help 🙂 or maybe try another plugin or write me own subscription form * thanks Jacek * Plugin Author [Carlo Roosen](https://wordpress.org/support/users/carloroosen/) * (@carloroosen) * [12 years, 1 month ago](https://wordpress.org/support/topic/sync-error/#post-4758476) * Hi Jarek, * I am happy to hear that. I will try it myself to see if the conflict can be resolved somehow. * On a sidenote: Do you use the same CM list to subscribe visitors? That will not work because our campaign-monitor-synchronization plugin will remove subscribers from CM that are not in the WP user list. If this is not what you want, consider our [http://wordpress.org/plugins/campaign-monitor-dual-registration](http://wordpress.org/plugins/campaign-monitor-dual-registration) plugin instead. * Thanks for reporting! * [jarzabjacek](https://wordpress.org/support/users/jarzabjacek/) * (@jarzabjacek) * [12 years, 1 month ago](https://wordpress.org/support/topic/sync-error/#post-4758477) * Hi Carlo, no we use different CM lists. Using your plugin we sync all users to a CM list and then with our custom user meta field passed during sync, we segment the list for approved, paid members etc. The other list is just for casual subscribers from our blog sidebar. * So its all good, all we need to sync all users to members CM list on cron-based intervals, exactly what your plugin does. * Just need to find another non-conflict way to add simple Subscription form to blog subscribers. * Let me know if you find a way to both your and AJax Forms plugin to work together * thanks Jacek * Plugin Author [Carlo Roosen](https://wordpress.org/support/users/carloroosen/) * (@carloroosen) * [12 years ago](https://wordpress.org/support/topic/sync-error/#post-4758504) * The issue was caused by another plugin ([http://wordpress.org/plugins/ajax-campaign-monitor-forms](http://wordpress.org/plugins/ajax-campaign-monitor-forms)) not using the latest CM library. * I contacted the author of this plugin and he fixed it. Viewing 11 replies - 1 through 11 (of 11 total) The topic ‘Sync error’ is closed to new replies. * ![](https://s.w.org/plugins/geopattern-icon/campaign-monitor-synchronization. svg) * [Campaign Monitor Synchronization](https://wordpress.org/plugins/campaign-monitor-synchronization/) * [Support Threads](https://wordpress.org/support/plugin/campaign-monitor-synchronization/) * [Active Topics](https://wordpress.org/support/plugin/campaign-monitor-synchronization/active/) * [Unresolved Topics](https://wordpress.org/support/plugin/campaign-monitor-synchronization/unresolved/) * [Reviews](https://wordpress.org/support/plugin/campaign-monitor-synchronization/reviews/) * 11 replies * 3 participants * Last reply from: [Carlo Roosen](https://wordpress.org/support/users/carloroosen/) * Last activity: [12 years ago](https://wordpress.org/support/topic/sync-error/#post-4758504) * Status: resolved