WebP not delivered from time to time

it’s due to the provider configuration for caches on server side , can not be solved by plugin side

Thank you qtwrk,

Can you tell me what’s causing the problem on the server side? Maybe I can contact the hosting provider and tell him about the problem.

when you enable webp , the cache will be saved into 2 varies

1 -> no webp vary

2-> webp vary

### marker WEBP start ###
RewriteCond %{HTTP_ACCEPT} "image/webp"
RewriteRule .* - [E=Cache-Control:vary=%{ENV:LSCACHE_VARY_VALUE}+webp]
RewriteCond %{HTTP_USER_AGENT} iPhone.*Version/(\d{2}).*Safari
RewriteCond %1 >13
RewriteRule .* - [E=Cache-Control:vary=%{ENV:LSCACHE_VARY_VALUE}+webp]
### marker WEBP end ###

that’s the part you see this rule in .htaccess about , it differentiates based on webp supportability

now , in your provider , they are running as Apache + LiteSpeed ADC (reverse proxy + cache )

as the rule is inserted into .htaccess, so ADC does NOT know this vary , so it will cache whoever-comes-first

like if a browser with no webp comes first, then ADC caches this page then later on serve to all following visitors even they support webp

or vice versa , if someone with webp support accessed it first, then ADC cached it with webp images , and serve to all following visitors even they have no webp supported-browser

bascially , the provider needs to insert this rule into ADC configuration as well , so ADC can be made aware of this vary

• This reply was modified 3 weeks, 1 day ago by qtwrk.

Thank you so much for your detailed answer! I will ask my provider about this issue.

• This reply was modified 2 weeks, 6 days ago by remiliko.