MALWAREBYTES has explained that some Yahoo Mail redirects are being blocked because background calls from the Yahoo Mail web interface reach third‑party domains that many security tools classify as risky.
The article notes that when you open Yahoo Mail, the page loads embedded components that contact domains such as cook.howduhtable[.]com and related subdomains, sometimes in URLs containing /ybar/mail.yahoo[.]com/ and an encoded parameter that often resolves to a sandboxed endpoint like https://gpt.mail.yahoo[.]net/sandbox?client=novation&version=0.1&haq=1&cache=1.
According to Malwarebytes, these signals—changing, opaque subdomains, encoded parameters, and chained redirects—are typical of infrastructure linked to malicious advertising and tracking, which is why Web Protection and Browser Guard block the related subdomains. The article emphasises that this does not mean Yahoo Mail itself is compromised, but that a narrow set of background calls within Yahoo Mail’s web experience presents elevated risk. Users may see web protection alerts referencing domains such as cook.howduhtable[.]com while reading or composing email.