Hi Friedrich,
I would recommend you to bring your question to Stackoverflow with the output of the equivalent gcloud command with the --log-http flag so the community have extra information to help you troubleshoot this issue. The command could look something like this :
gcloud sql export sql [INSTANCE_NAME] [BUCKET_NAME]/sqldumpfile.gz\ --database=[DATABASE_NAME]\
--log-http
Hello,
After doing some investigation, this may be caused by multiple factors. Good information would be to know if it happens every time or only with large files in which case it would probably be an issue on our end that would need to be investigated. Hence, In order to properly troubleshoot this issue, you would need to create a Google Issue Tracker about this so the proper support can be provided since Google Groups is meant for conceptual questions and discussions and this would fall more into an issue troubleshooting for which Google Issue Tracker or Stack overflow would be more indicated.