Unable to download yarn on leshan jenkins CI

Since las friday (March 18th), I didn't get a successful build of https://ci.eclipse.org/leshan/job/leshan/

They all failed with:

[ERROR] Failed to execute goal com.github.eirslett:frontend-maven-plugin:1.12.1:install-node-and-yarn (install node and yarn) 
on project leshan-server-demo:
Could not download Yarn: Could not download https://github.com/yarnpkg/yarn/releases/download/v1.22.10/yarn-v1.22.10.tar.gz: 
Unknown host objects.githubusercontent.com: Temporary failure in name resolution 

Surprisingly, last https://ci.eclipse.org/leshan/job/leshan-nightly/ which happened on Match 19th succeed and it also download node and yarn :

[INFO] --- frontend-maven-plugin:1.12.1:install-node-and-yarn (install node and yarn) @ leshan-server-demo ---
[INFO] Installing node version v12.22.5
[INFO] Downloading https://nodejs.org/dist/v12.22.5/node-v12.22.5-linux-x64.tar.gz to /home/jenkins/.m2/repository/com/github/eirslett/node/12.22.5/node-12.22.5-linux-x64.tar.gz
[INFO] No proxies configured
[INFO] No proxy was configured, downloading directly
[INFO] Unpacking /home/jenkins/.m2/repository/com/github/eirslett/node/12.22.5/node-12.22.5-linux-x64.tar.gz into /home/jenkins/agent/workspace/leshan-nightly/leshan-server-demo/webapp/node/tmp
[INFO] Copying node binary from /home/jenkins/agent/workspace/leshan-nightly/leshan-server-demo/webapp/node/tmp/node-v12.22.5-linux-x64/bin/node to /home/jenkins/agent/workspace/leshan-nightly/leshan-server-demo/webapp/node/node
[INFO] Installed node locally.
[INFO] Installing Yarn version v1.22.10
[INFO] Downloading https://github.com/yarnpkg/yarn/releases/download/v1.22.10/yarn-v1.22.10.tar.gz to /home/jenkins/.m2/repository/com/github/eirslett/yarn/1.22.10/yarn-1.22.10.tar.gz
[INFO] No proxies configured
[INFO] No proxy was configured, downloading directly
[INFO] Unpacking /home/jenkins/.m2/repository/com/github/eirslett/yarn/1.22.10/yarn-1.22.10.tar.gz into /home/jenkins/agent/workspace/leshan-nightly/leshan-server-demo/webapp/node/yarn
[INFO] Installed Yarn locally.

So I'm not sure what happens here. 🤷
Any idea ? 🙏