Cristofer Gross
Post count: 3
#22869 |

In trying to improve SEO by following Yoast SEO tutorial, I began by trying to add and “claim” Alexa. I claimed it, got a verification number by adding a plugin and now I get this message and my site theme has been altered.

Warning: Cannot modify header information – headers already sent by (output started at /home/content/p3pnexwpnas09_data03/64/2474564/html/wp-includes/plugin.php:503) in /home/content/p3pnexwpnas09_data03/64/2474564/html/wp-includes/pluggable.php on line 1207

I can deactivate the Yoast and Alexa plugins but can’t delete them, because a similar message comes up.