Hello,
Apologies for the problem with the error message with BoldGrid. Please try disabling the SEO plugin in the plugins section. You can do it manually by going to the files for your WordPress installation, then going to the plugins folder and renaming the boldgrid-seo folder. After you do that, try logging into your BoldGrid site. If you’re able to login, please provide us the version of the plugin that you’re using. It’s possible that the plugin is conflicting with something else. If you require assistance with this, please contact your hosting technical support team. Also, please try to reload the plugin and see if it helps.
Double-check to see if another plugin is conflicting (non-BoldGrid), but disabling them and then renabling them one-by-one while the BoldGrid SEO plugin is running. This would be after re-loading the BoldGrid SEO plugin and making sure that all other plugins are turned off. This should help isolate what is causing the problem. On WordPress sites running BoldGrid, there is no reported history of the SEO plugin causing a fatal error at present, so this is a new issue. Please provide us with this information and we can investigate the issue in more depth.