What are the issues with ESPs sending unsolicited marketing emails through other ESPs?

Email marketer from Quora responds that unsolicited emails lead to lower open rates, click-through rates, and higher unsubscribe rates, ultimately damaging your email marketing ROI.

Marketer from Email Geeks asks if the scenario is where an ESP is sending cold emails advertising itself through a different ESP.

Email marketer from Stack Overflow shares that remediating the damage caused by sending unsolicited emails (e.g., unblocking IPs, improving sender reputation) can be costly and time-consuming.

Email marketer from Litmus blog explains that sending unsolicited emails can tarnish your brand's reputation, potentially leading to long-term damage and loss of customers.

Email marketer from G2 answers that using another ESP can lead to list bombing issues where you get added to lists without your permission which is really bad.

Email marketer from Reddit comments that sending unsolicited emails erodes user trust in your brand, making them less likely to engage with your future legitimate campaigns.

Email marketer from Email On Acid Blog shares that high spam complaint rates resulting from unsolicited emails can negatively affect your deliverability across all campaigns, not just the unsolicited ones.

Email marketer from Mailjet highlights that sending unsolicited emails violates anti-spam laws like GDPR and CAN-SPAM, leading to potential fines and legal repercussions.

Email marketer from Neil Patel's Blog explains that sending unsolicited emails can severely damage your sender reputation, leading to ISPs and email providers blocking your messages.

Expert from Email Geeks explains the issue is that someone is sending mail to addresses that haven’t requested it and offloading the reputation hit for spamming onto one of their competitors.

Expert from Spam Resource explains that using another ESP to send unsolicited emails is a form of proxying and harms the reputation of the proxied ESP, leading to potential blacklisting and deliverability issues for the legitimate users of that ESP.

Expert from Word to the Wise shares the use of other ESPs to send unsolicited emails ultimately damages your brand's reputation, and leads to negative brand perception from potential customers.

Documentation from Microsoft SNDS clarifies that sending unsolicited emails can lead to IP addresses being blocked by Microsoft's email services (Outlook, Hotmail), severely affecting deliverability to those users.

Documentation from Spamhaus explains if someone uses another ESP for cold emails, this can lead to blocklist placement because that is against Spamhaus' policy.

Documentation from RFC-Editor.org explains that when an ESP sends unsolicited emails through another ESP, it can cause authentication failures (SPF, DKIM, DMARC) for the legitimate sending domain, negatively impacting deliverability.

Documentation from Google Postmaster Tools indicates that sending unsolicited emails negatively impacts the sender's domain reputation in Google's eyes, leading to more emails landing in the spam folder.