[INFO] Building Reference Application Module OMOD 2.7.0-SNAPSHOT
[INFO] ------------------------------------------------------------------------
[WARNING] The POM for rubygems:sass:gem:3.4.21 is missing, no dependency information available
[INFO] ------------------------------------------------------------------------
[INFO] Reactor Summary:
[INFO]
[INFO] Reference Application Module ....................... SUCCESS [  0.776 s]
[INFO] Reference Application Module API ................... SUCCESS [ 56.847 s]
[INFO] Reference Application Module OMOD .................. FAILURE [  0.420 s]
[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 01:01 min
[INFO] Finished at: 2017-11-20T13:12:35+01:00
[INFO] Final Memory: 39M/291M
[INFO] ------------------------------------------------------------------------
[ERROR] Failed to execute goal on project referenceapplication-omod: Could not resolve dependencies for project org.openmrs.module:referenceapplication-omod:jar:2.7.0-SNAPSHOT: Failure to find rubygems:sass:gem:3.4.21 in http://mavenrepo.openmrs.org/nexus/content/repositories/public was cached in the local repository, resolution will not be reattempted until the update interval of openmrs-repo has elapsed or updates are forced -> [Help 1]
[ERROR]
[ERROR] To see the full stack trace of the errors, re-run Maven with the -e switch.
[ERROR] Re-run Maven using the -X switch to enable full debug logging.
[ERROR]
[ERROR] For more information about the errors and possible solutions, please read the following articles:
[ERROR] [Help 1] http://cwiki.apache.org/confluence/display/MAVEN/DependencyResolutionException
[ERROR]
[ERROR] After correcting the problems, you can resume the build with the command
[ERROR]   mvn <goals> -rf :referenceapplication-omod