We'll look into the IPv6/firewall issue and try to fix that - thanks for the report (and thanks @HiassofT for the temporary workaround!)
Texture Cache Maintenance Utility: Preload your texture cache for optimal UI performance. Remotely manage media libraries. Purge unused artwork to free up space. Find missing media. Configurable QA check to highlight metadata issues. Aid in diagnosis of library and cache related problems.