Description: You get a warning message on your browser that says:
Warning: Cannot modify header information - headers already sent by (output started atâ€¦
Reason and Solution :
It is usually because there are spaces, new lines, or other garbage before an opening <?php tag or after a closing ?> tag, typically in wp-config.php. This could be true about some other file too, so please check the error message, as it will list the specific file name where the error occurred.
Just because you cannot see anything does not mean that PHP sees the same.
Download the file mentioned in the error message.
Open that file in a plain text editor (NOT MS Word or similar. Notepad or BBEdit are fine).
Check that the very first characters are <?php
Check that the very last characters are ?>
To be sure about the end of the file, do this:
1. Place the cursor between the ? and >
2. Now press the DELETE key on your computer
3. Keep it pressed
4. For at least 15 seconds
5. Now type > and
6. save without pressing any other key at all.
7. If you press another key, you will bring the problem back.