How do subdomain spam complaints affect root domain reputation in Google Postmaster Tools?

Email marketer from Litmus mentions that subdomain deliverability is a factor, and while a healthy root domain can withstand some subdomain issues, persistent high spam complaints from the subdomain can lead to deliverability problems.

Email marketer from StackOverflow suggests that subdomains and root domains can be linked via shared IP addresses or DKIM records, meaning spam complaints from one can impact the deliverability of the other.

Marketer from Email Geeks explains that the same escalation of negative reputation from a single IP to a /24 could potentially happen from a subdomain to a domain.

Email marketer from SendPulse mentions that a negative reputation on a subdomain due to spam complaints can affect the deliverability of emails sent from the root domain, as ISPs might associate the two.

Email marketer from Mailjet shares that when a subdomain sends spam, ISPs may associate that behavior with the root domain, potentially damaging the root domain's sending reputation and deliverability.

Email marketer from Reddit shares from experience that Google's algorithm can sometimes associate negative subdomain behavior with the root domain, leading to temporary dips in root domain reputation, especially if sending volume from both is similar.

Email marketer from Neil Patel Digital explains that a poor subdomain reputation can negatively affect the overall brand reputation and potentially lead to deliverability issues for the root domain, especially if authentication protocols aren't properly configured.

Email marketer from Email on Acid explains that incorrect authentication protocols, if used the same across subdomains and the root domain, may result in spam complaints in one domain affecting the other.

Email marketer from Gmass highlights that spam complaints, whether they arise in the root domain or subdomain, can significantly impact the reputation of the sender, which subsequently affects deliverability rates.

Email marketer from SparkPost explains that while using subdomains can segment sending reputation, consistent spam issues on a subdomain can still reflect poorly on the overall brand and potentially impact root domain deliverability over time.

Expert from Email Geeks shares an analogy, stating that a root domain can be impacted by a subdomain's actions similar to how a family can be affected by one member's misdeeds.

Expert from Spamresource explains that if you are on a shared IP, even if a subdomain is the culprit, the IP will be added to a blocklist and because you are sharing, you may be affected.

Expert from Word to the Wise explains that when warming up new IP Addresses and subdomains, it's important to segment sending carefully, because negative behavior on a new subdomain could have a disproportionate effect on your root domain's reputation if not managed correctly during the initial reputation building phase.

Documentation from Microsoft 365 Defender Documentation highlights that sender reputation is partially based on domain reputation, and while subdomains can have independent reputations, consistently high spam complaints from a subdomain can flag the entire organizational domain (including the root).

Documentation from DMARC.org outlines that a strong DMARC policy, while protecting against spoofing, can also expose poor sending practices on subdomains, leading to increased spam complaints that could indirectly affect the root domain’s reputation if not managed properly.

Documentation from RFC details that authentication standards like SPF and DKIM, when misconfigured across subdomains and root domains, can inadvertently link their reputations, making it easier for spam complaints on one to affect the other.

Documentation from Google Postmaster Tools Help details that while subdomains can have independent reputations, significant spam complaints on a subdomain *can* negatively impact the overall reputation of the root domain, particularly if sending practices are similar across both.