The error message indicates that your system is unable to reach Docker’s official repository server within a certain timeframe. In technical terms, exit code 28 is CURLE_OPERATION_TIMEDOUT , meaning the connection was attempted but never completed.
This issue commonly arises when installing or updating Docker on Linux, as the curl command is used to pull the necessary installation scripts or GPG keys. Common Causes Rocky Linux Forum Failed to connect to download.docker.com port 443 curl (28) failed to connect to download.docker.com port 443