Wordpress LScache Plugin: Generate Critical CSS
Last Updated on: Wed, 15 Apr 2026 00:00:02 Hi, Ive read on your website about Load CSS Asynchronously and Generate Critical CSS. And in your guidelines it says that I should see the tag in the html document , which I do see, but the ccss doesnt seem to be generated. And then I read a line that says you may need to whitelist our remote CCSS server: ccss.api.litespeedtech.com . Is this the culprit for not generating the ccss? If yes, can you please tell me how exactly do I whitelist that domain and where? Thank you. Hi, Please check this wiki If you set CCSS generation in background , then that could happen , in this case, purge LS cache and try again. For whitelist, you need to have root access to your server, and add the IP of ccss.api.litespeedtech.com to your firewall. You may need to contact your hosting provider for this. Best regards, Hi @CacheCrawler, Thank you for the response. So if I dont use the CCSS generation in background, I dont need to whitelist the IP anymore? Hi, Not exactly , these are 2 different things, but first please try set CCSS generation in foreground see if it works out , if so then you dont need to whitelist it anymore. and please do remember purge all after you changed setting. Best regards, Well, I did set the CCSS generation in background to OFF, and I purged all. But I still get the FOUC and the in still doesnt generate anything. Hi, Could you please provide the report number ? Best regards, Report number: DWLKVXKE Hi, Please try enable debug log add your IP and IPs in this list to admin IP box, purge all cache and access your homepage 2 twice and check the log. Best regards, This is what I get: 01/21/19 13:39:53.434 [93.119.153.4:51260 1 18c] [Media] posting to : https://wp.api.litespeedtech.com/placeholder/681x724?v=2.8.1&c=I2ZmZmZmZg== 01/21/19 13:39:53.922 [93.119.153.4:51260 1 18c] [Media] failed to decode response: 404 Not Found 404 Not Found The resource requested could not be found on this server! Hi, I see your LSCWP is still 2.8.1 , please try upgrade to 2.9. Best regards, Yep, now it works, after the upgrade to 2.9. However, there is still a slight FOUC when accessing pages. Can this be completely eliminated somehow? Hi, I still dont see the corresponding litespeed-optm-css-rules in your source code. Please double check if you have it correctly enabled Best regards, I have disabled it, since the FOUC is way too annoying. I was expecting to see no kind of flashes whatsoever. In addition, it messes up the format of the products in Shop page (the first row displays only 1 product, out of 2) while on Mobile. Hi, Could you please submit a ticket ? Wed like to know more details about this issue. Best regards,
LiteCache Rush: Speed comes from using less, not from doing it faster
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