ERR_CONNECTION_TIMED_OUT on AWS S3
Why it happens on AWS S3
A security group or network ACL that allows your office IP but not the public internet makes an S3-backed site or its origin time out for everyone else.
The fix on AWS S3
Review the security group's inbound rules for ports 80/443 and the bucket policy's public-read settings. Test from a network outside your allowlist before declaring it fixed.
Is ERR_CONNECTION_TIMED_OUT happening on your domain?
An uptime probe from outside your network tells you whether the server is unreachable for everyone or only from where you are sitting — which is the first fork in every timeout diagnosis.
Free, no signup. Runs from outside your network, which is the only way to tell a server fault from a local one.
If that didn't fix it
AWS S3 has its own failure mode, but ERR_CONNECTION_TIMED_OUT has a wider set of causes that apply everywhere. The most common one overall is: the origin server is down or the web server process has stopped.
All causes and fixes for ERR_CONNECTION_TIMED_OUT