The sender email reputation is always based on the domain and its emails reputation. You must always careful to keep your email scores higher. If you keep sending emails to an Undelivered, Spam, Risky, Invalid emails your email score will go low. So when ever you send email to the recipients it may land to spam box instead of inbox. If you are doing bulk emailing then its always recommended to verify the list before sending out an email blast.
Choose a Best Email Verification Software BounceKick. It has an Self-Hosted and SaaS model of deployments.
By verifying/validating your email list before sending out a campaign you can identify which of them should be used (valid) and which would end up resulting in bounces(damaging your sending reputation).
A high amount of bounces will result in damaging your sending reputation and end up getting you blacklisted, and it will prevent you from launching future campaigns.
It is highly important for any email marketer to maintain good email hygiene, thus a healthy reputation. Also using a highly accurate service such as Zerobounce lowers the risk of encountering unwanted bounces.