Recently, I saw many warning message in error log of litespeed web server like this:
PHP Warning: Cannot modify header information – headers already sent in /wp-content/plugins/litespeed-cache/src/vary.cls.php on line 735
and noticed that web pages are not cached correctly, the cache function does not work, which slow down the web page serving speed.
the litespeed cache plugin team need to fix the bug in the next update. the temporary solution is to turn off the Guest Mode in Litespeed cache plugin’s General Settings.
