Title: Multisite and Warning: Cannot modify header information
Last modified: August 20, 2016

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# Multisite and Warning: Cannot modify header information

 *  [handig](https://wordpress.org/support/users/handig/)
 * (@handig)
 * [13 years, 7 months ago](https://wordpress.org/support/topic/multisite-and-warning-cannot-modify-header-information/)
 * Hi,
    Had the “Warning: Cannot modify header information – headers already sent
   by” warning again today when setting up a new wordpress multisite. I know it 
   is related to whitespaces and checked my plugins.
 * I notice that a lot of plugins have those whitespaces at the end.
 * So out of curiosity. Is this something that is introduced by new WP versions 
   being more ‘strict on whitespaces’ or is multisite more vulnerable to those little
   bastards?

Viewing 1 replies (of 1 total)

 *  Moderator [Ipstenu (Mika Epstein)](https://wordpress.org/support/users/ipstenu/)
 * (@ipstenu)
 * 🏳️‍🌈 Advisor and Activist
 * [13 years, 7 months ago](https://wordpress.org/support/topic/multisite-and-warning-cannot-modify-header-information/#post-3175394)
 * Neither, you should have had the same errors in singlesite.

Viewing 1 replies (of 1 total)

The topic ‘Multisite and Warning: Cannot modify header information’ is closed to
new replies.

## Tags

 * [plugin-development](https://wordpress.org/support/topic-tag/plugin-development/)
 * [white spaces](https://wordpress.org/support/topic-tag/white-spaces/)

 * In: [Networking WordPress](https://wordpress.org/support/forum/multisite/)
 * 1 reply
 * 2 participants
 * Last reply from: [Ipstenu (Mika Epstein)](https://wordpress.org/support/users/ipstenu/)
 * Last activity: [13 years, 7 months ago](https://wordpress.org/support/topic/multisite-and-warning-cannot-modify-header-information/#post-3175394)
 * Status: not resolved

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