Unable to download open saml jar while building the project

Question

While building my project I am getting unknown host exception while downloading the org.opensaml:opensaml:jar:2.6.6 jar.

I am using below dependencies in my project. And error I was receiving is as below.

<dependency>
    <groupId>org.springframework.security.extensions</groupId>
    <artifactId>spring-security-saml2-core</artifactId>
    <version>1.0.10.RELEASE</version>
    </dependency>
<dependency>
    <groupId>org.opensaml</groupId>
    <artifactId>opensaml</artifactId>
    <version>2.6.1</version>
</dependency>

Error:
Could not resolve dependencies for project security:jar:1.0.0: Failed to collect dependencies at org.springframework.security.extensions:spring-security-saml2-core:jar:1.0.10.RELEASE -> org.opensaml:opensaml:jar:2.6.6: Failed to read artifact descriptor for org.opensaml:opensaml:jar:2.6.6: Could not transfer artifact org.opensaml:opensaml:pom:2.6.6 from/to central (https://repo.maven.apache.org/maven2/): transfer failed for https://repo.maven.apache.org/maven2/org/opensaml/opensaml/2.6.6/opensaml-2.6.6.pom: Unknown host No such host is known (repo.maven.apache.org) -> [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