Error Codes in WordPress – Cannot Modify Header Information
When trying to login to your newly configured/built WordPress site are you getting this error?
Cannot modify header information – headers already sent by (output started at blah, blah, blah)
For me, it was an extra return in a database entry, specifically in wp_options where the site name (or WordPress URL) are defined. Go into cPanel then phpMyAdmin, and get rid of any extra spaces or returns in the wp_options Site URL and Home URL and make your life happy by avoiding an hour of troubleshooting like I had to do.
This came about from being too clever. I had changed this in cPanel – normally you’d do it in WordPress when you set up the site.
The site had been up and running as a subdomain for testing purposes but was moved to an addon domain with it’s own domain name when it went live. This necessitated using cPanel to make the change, which I’d done before so it wasn’t a big deal. Unless you unknowingly enter the extra space or return. Then you’re looking at hours of frustration.
Logical, it makes sense, now that I’ve gone through it. Of course it can’t change header info if the header you’re telling it to modify isn’t there. But a “space”? It’s the biggest key on the board, you’d think by now that most programs would have figured out that a space after or before is to be ignored and not part of the string.
Now you know.