Error 504 (Gateway Time-out) during Maven deploy

I'm currently trying to deploy a new version of our project to the Sonatype staging repository but the upload always fails with a Gateway Time-out.

After building and signing the release artifacts I run `mvn deploy` which fails as follows:

[...]
[INFO] — maven-deploy-plugin:2.7:deploy (default-deploy) @ graylog2-parent —
Uploading: https://oss.sonatype.org/service/local/staging/deploy/maven2/org/graylog2/graylog2-parent/0.92.0-beta.1/graylog2-parent-0.92.0-beta.1.pom
[...]
Here it stalls for quite some time
[...]
[ERROR] Failed to execute goal org.apache.maven.plugins:maven-deploy-plugin:2.7:deploy (default-deploy) on project graylog2-parent: Failed to deploy artifacts: Could not transfer artifact org.graylog2:graylog2-parent:pom:0.92.0-beta.1 from/to sonatype-nexus-staging (https://oss.sonatype.org/service/local/staging/deploy/maven2/): Failed to transfer file: https://oss.sonatype.org/service/local/staging/deploy/maven2/org/graylog2/graylog2-parent/0.92.0-beta.1/graylog2-parent-0.92.0-beta.1.pom. Return code is: 504, ReasonPhrase: Gateway Time-out. -> [Help 1]

Is that a temporary problem on your side or do you have any hint for me on how to fix this?

If it helps, I've successfully uploaded numerous artifacts to the Sonatype snapshot and staging/release repositories in the past.

Thanks!