Title: PHP Warning
Last modified: June 14, 2023

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# PHP Warning

 *  [Webset.dk](https://wordpress.org/support/users/websetdk/)
 * (@websetdk)
 * [2 years, 11 months ago](https://wordpress.org/support/topic/php-warning-434/)
 * I get this error in error_log
   “PHP Warning: Cannot modify header information –
   headers already set in ……./plugins/woo-postfinance-checkout/woocommerce-postfinancecheckout.
   php on line 539”.This happens for multible domains.
 * The page I need help with: _[[log in](https://login.wordpress.org/?redirect_to=https%3A%2F%2Fwordpress.org%2Fsupport%2Ftopic%2Fphp-warning-434%2F%3Foutput_format%3Dmd&locale=en_US)
   to see the link]_

The topic ‘PHP Warning’ is closed to new replies.

 * ![](https://ps.w.org/woo-postfinance-checkout/assets/icon-256x256.png?rev=2919636)
 * [PostFinance Checkout](https://wordpress.org/plugins/woo-postfinance-checkout/)
 * [Support Threads](https://wordpress.org/support/plugin/woo-postfinance-checkout/)
 * [Active Topics](https://wordpress.org/support/plugin/woo-postfinance-checkout/active/)
 * [Unresolved Topics](https://wordpress.org/support/plugin/woo-postfinance-checkout/unresolved/)
 * [Reviews](https://wordpress.org/support/plugin/woo-postfinance-checkout/reviews/)

 * 0 replies
 * 1 participant
 * Last reply from: [Webset.dk](https://wordpress.org/support/users/websetdk/)
 * Last activity: [2 years, 11 months ago](https://wordpress.org/support/topic/php-warning-434/)
 * Status: not resolved