Does using a subdomain always solve deliverability issues?

Myth: False. Subdomains do not automatically solve deliverability issues. Subdomain reputation connects to parent domain reputation. Problems on the main domain can affect subdomains.

Subdomains are useful for separating mail streams and building distinct reputations for different purposes. But they are not escape hatches from main domain problems.

Use subdomains strategically for mail stream separation. Do not expect them to bypass reputation issues. Address root causes regardless of domain structure.