Please use https when accessing nexus.magnolia-cms.com.

https://nexus.magnolia-cms.com/content/repositories/magnolia.public.releases//info/magnolia/magnolia-module-imaging/3.0.1/magnolia-module-imaging-3.0.1.jar.

Please also update your settings.xml

Please update your projects to use the latest parent poms, at least version 29.