Re: Activation link show me errors
We seem to be seeing more and more of this particular type of issue. It makes me wonder. Hum…
But, let’s start with your error message. I’m going to repeat verbatim what I said in two other threads.
The “Cannot modify header” error almost always indicates that there is some extra stuff (whitespace, extra text) before the opening php or closing php tag. It could be in one or both places. There must not be anything before or after the opening and closing PHP tags–not a single space, not any extra characters, not a single carriage return.
Open up header.php in your custom theme file and look for any whitespace or extra stuff. It should be removed and the file saved.
Report back on what you found and if that helps.
Here’s more information of the “Cannot modify header” error: https://codex.wordpress.org/Answers-Troubleshooting#Headers_already_sent
