This is youtube it is probably trying to get the cover image for a youtube video and is failing, try pinging and doing a tracert to that domain see what you get maybe you have a DNS issue or something similar...
Static asset is anything that isn't dynamic... IE stylesheet images etc... dynamic content IE .php files etc get loaded from the normal domain and dynamic content gets loaded from the CDN (content delivery network/cookieless domain name).
What is happening is this:
I ping i4.ytimg.com and this ip address keeps showing up: 22.214.171.124 - which keeps timing out for me and the ATT support tech person.
When I go to nwtools.com and test i4.ytimg.com resolves to 126.96.36.199, .2, .7 - all of which work great.
Could any kind soul give me an idea how I can get i4.ytimg.com to resolve to a different ip?
I ping youtube and it came back with 188.8.131.52 & 184.108.40.206 which both work great.
I would normally say this is not an xf issue (and it isn't), but this is probably important for forums owners in general. I know one forum in particular that has had an ongoing issue connecting to fb, youtube, and of course google ads. They are loosing much traffic over erratic operation and I think this could be the reason.
Any ideas how to resolve i4.ytimg.com to a different url? Or even some way to independently confirm I am using open source dns?
1) Your ISP network that lies between you and the Google servers, obviously has some issues.
2) Changing your DNS won't fix the networking issue between you and Google.
3) Do a tracer to the target server to determine who's router is dropping the ball.
As for forum owners: Anytime you implement a 3rd party tool, plug-in or any other type of data piece that refers to a location other your own domain, you can always expect to have a certain percentage of users that will have increased access times to those services. Thus, those users will complain, but anything not hosted on your own equipment is generally out of your control. Downstream network problems that fall on another provider, are also generally out of your control.
It's not your forum that's connecting to the additional services, it's the user themselves.