Firewalls can affect email deliverability in several ways:
Blocking IP Addresses: Firewalls can block specific IP addresses that are known to send spam. If your IP address gets blacklisted, your emails won't reach the recipients. Content Filtering: Firewalls often filter emails based on their content. If your email contains suspicious links or attachments, it may get blocked. Rate Limiting: Some firewalls limit the number of emails that can be sent or received within a certain timeframe. This can affect high-volume email campaigns.