rsync: failed to connect to rsync.macports.org: Operation timed out (60)

~~~~@~~~~~~~ % sudo port -v selfupdate
Password:
--->  Checking for newer releases of MacPorts
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100    63  100    63    0     0   1573      0 --:--:-- --:--:-- --:--:--  1575
MacPorts base version 2.10.0 installed,
MacPorts base version 2.10.0 available.
--->  MacPorts base is already the latest version
--->  Updating the ports tree
Synchronizing local ports tree from rsync://rsync.macports.org/macports/release/tarballs/ports.tar.gz
rsync: failed to connect to rsync.macports.org: Operation timed out (60)
rsync error: error in socket IO (code 10) at /AppleInternal/Library/BuildRoots/4ff29661-3588-11ef-9513-e2437461156c/Library/Caches/com.apple.xbs/Sources/rsync/rsync/clientserver.c(109) [receiver=2.6.9]
Command failed: /usr/bin/rsync -rtzvl --delete-after --include=/ports.tar.gz --include=/ports.tar.gz.rmd160 --exclude=* rsync://rsync.macports.org/macports/release/tarballs/ /opt/local/var/macports/sources/rsync.macports.org/macports/release/tarballs
Exit code: 10
Error: Synchronization of the local ports tree failed doing rsync
Error: Couldn't sync the ports tree: Synchronization of 1 source failed
Error: Follow https://guide.macports.org/#project.tickets if you believe there is a bug.
Error: /opt/local/bin/port: port selfupdate failed: Couldn't sync the ports tree: Synchronization of 1 source failed

I have error while self-updating port, how can I fix it?

I’ve tried several ways to troubleshoot it, but it doesn’t work.