There are no indications that this is a malicious domain; however, users often investigate these strings when they appear in firewall logs, browser history, or network analytics, raising questions about data transmission.
Your upstream DNS provider (e.g., Cloudflare 1.1.1.1, Google 8.8.8.8) may be having issues, or a firewall/DPI box is blocking the domain. tb-rg adguard.net