I have created a new project in android studio 3.0.1 setup the proxy settings of company and added the self sighned certificate unser server sertificates. When I try to build the following error is listed and the build fails. 

Error:

```
Unable to resolve dependency for ':app@debug/compileClasspath': Could not resolve com.android.support:appcompat-v7:26.1.0.

Could not resolve com.android.support:appcompat-v7:26.1.0.
Required by:
    project :app
 > Could not resolve com.android.support:appcompat-v7:26.1.0.
    > Could not get resource 'https://dl.google.com/dl/android/maven2/com/android/support/appcompat-v7/26.1.0/appcompat-v7-26.1.0.pom'.
          > Could not GET 'https://dl.google.com/dl/android/maven2/com/android/support/appcompat-v7/26.1.0/appcompat-v7-26.1.0.pom'.
                   > sun.security.validator.ValidatorException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target
                               > PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target
                                              > unable to find valid certification path to requested target

```

Could somebody help me?