If you get such a connection error for all new artifacts: m2eclipse uses an embedded Maven instance by default, not your external Maven installation. The internal Maven instance might not use the same Maven settings like your external one (e.g. %USERPROFILE%/.m2/settings.xml), which then might lead to the internal Maven instance not being able to connect through your proxy.
You can use the Eclipse preferences to add your external Maven installation and to have it be used for running Maven commands from inside Eclipse.
This is very short tip to resolve the error “ArtifactTransferException: Could not transfer artifact” that may occur in Maven project in Eclipse.
Steps to resolve:
1. Open folder by running this text (without Quotes) in Search Explorer of Window “%USERPROFILE%\.m2″.
2. After running above command, “m2″ folder of maven will open. Now search for file (without Quotes) “*.lastUpdated”.
3. In this step, delete all the files found by running Step 2.
4. Now go to Eclipse project and select “Maven | Update Dependency” or “Maven | Update Project”.
Happy Coding.
This is my solution.
find jar libraries that error occurred and delete from .m2 repo. Then update project using m2eclipse. It works for me.