Images or CSS in IPFS pages are not rendered and time out

If there are links to images or even css files in an html page then loaded on IPFS, once the request has been made from the outside using the public DNS (https://ipfs.io/ipfs/) the page itself times out. Do you have any idea why this happens and how to fix this problem?

This is the test that I published: https://ipfs.io/ipfs/QmPoSRk1TzM3YC2qiCFDjnKtJZ9FR6jRVNrP2nNSu4cJMi