Title: Warning: Undefined array key ….
Last modified: February 25, 2025

---

# Warning: Undefined array key ….

 *  [ehsan06](https://wordpress.org/support/users/ehsan06/)
 * (@ehsan06)
 * [1 year, 3 months ago](https://wordpress.org/support/topic/warning-undefined-array-key-31/)
 * Please HELP!
   I got these error, not knowing what I’ve done wrong! This shows 
   up on top of every product page! How do I fix it???“**Warning**: Undefined array
   key “last_modified” in **/var/www/vhosts/utoms.se/httpdocs/wp-content/plugins/
   wp-optimize/minify/class-wp-optimize-minify-front-end.php** on line **1408**
 * **Warning**: Undefined array key “last_modified” in **/var/www/vhosts/utoms.se/
   httpdocs/wp-content/plugins/wp-optimize/minify/class-wp-optimize-minify-front-
   end.php** on line **1408**“
 * The page I need help with: _[[log in](https://login.wordpress.org/?redirect_to=https%3A%2F%2Fwordpress.org%2Fsupport%2Ftopic%2Fwarning-undefined-array-key-31%2F%3Foutput_format%3Dmd&locale=en_US)
   to see the link]_

Viewing 2 replies - 1 through 2 (of 2 total)

 *  Moderator [threadi](https://wordpress.org/support/users/threadi/)
 * (@threadi)
 * [1 year, 3 months ago](https://wordpress.org/support/topic/warning-undefined-array-key-31/#post-18327139)
 * The message is caused by the WP Optimize plugin you are using. I would recommend
   you to contact their support forum: [https://wordpress.org/support/plugin/wp-optimize/](https://wordpress.org/support/plugin/wp-optimize/)
 *  Thread Starter [ehsan06](https://wordpress.org/support/users/ehsan06/)
 * (@ehsan06)
 * [1 year, 3 months ago](https://wordpress.org/support/topic/warning-undefined-array-key-31/#post-18327200)
 * Thank you! Ill contact the immediately 🙏

Viewing 2 replies - 1 through 2 (of 2 total)

The topic ‘Warning: Undefined array key ….’ is closed to new replies.

 * In: [Fixing WordPress](https://wordpress.org/support/forum/how-to-and-troubleshooting/)
 * 2 replies
 * 2 participants
 * Last reply from: [ehsan06](https://wordpress.org/support/users/ehsan06/)
 * Last activity: [1 year, 3 months ago](https://wordpress.org/support/topic/warning-undefined-array-key-31/#post-18327200)
 * Status: not resolved

## Topics

### Topics with no replies

### Non-support topics

### Resolved topics

### Unresolved topics

### All topics