Try downloading the file manually from the project website.
Then, install it using the command:
mvn install:install-file -DgroupId=org.glassfish.external
-DartifactId=gri
zzly-module \
-Dversion=1.8.6-RC2 -Dpackaging=jar -Dfile=/path/to/file
Alternatively, if you host your own repository you can deploy the file
there:
mvn deploy:deploy-file -DgroupId=org.glassfish.external
-DartifactId=grizzly
-module \
-Dversion=1.8.6-RC2 -Dpackaging=jar -Dfile=/path/to/file \
-Durl=[url] -DrepositoryId=[id]
Path to dependency:
1) org.glassfish.common:glassfish-api:hk2-jar:10.0.415
2) org.glassfish.external:grizzly-module:jar:1.8.6-RC2
----------
1 required artifact is missing.
for artifact:
org.glassfish.common:glassfish-api:hk2-jar:10.0.415