Building open-source Maven project - SOAPUI - dependency issue cajo v1.142

After cloning git repo https://github.com/SmartBear/soapui.git, and trying the build the project with Maven, there is an error with downloading the dependency gnu.cajo cajo v1.142

Also downloading through a browser shows a network error.
http://smartbearsoftware.com/repository/maven2/gnu/cajo/cajo/1.142/

It is not easy to find the jar through another Maven repository.

Can someone check why downloading this jar gives a network error?

Running the Maven job through a different network, is a workaround. Checking the log, maybe shows what causes the issue, from the company network.

[DEBUG] Using connector AetherRepositoryConnector with priority 3.4028235E38 for http://www.soapui.org/repository/maven2/

[INFO] Downloading: http://www.soapui.org/repository/maven2/gnu/cajo/cajo/1.142/cajo-1.142.jar

[WARNING] Checksum validation failed, no checksums available from the repository for http://www.soapui.org/repository/maven2/gnu/cajo/cajo/1.142/cajo-1.142.jar