IP blacklisting occurs when your internet IP address is added to a list of known sources of spam or malicious activity. When you connect with your internet then you will be allocated normally a shared internet IP address that changes everytime you restart the internet router. If your internet IP is already blacklisted then some of the email service providers (sender/receiver) will block email/traffic to protect their network which can result in emails not being delivered to intended recipients.
Your internet IP address and your email server IP address both are different as we are responsible to arrange the whitelist of your email server IP address and for the internet IP address you will need to speak with your internet service provider. If your internet IP address is static/dedicated then as complimentary we can arrange the whitelist your IP address from the blacklisting companies but If your internet IP is dynamic and changes everytime you restart the router then it will be useless because the IP will change constantly. The best practice is to ask your internet service provider to allocate you whitelisted IP address so your email may go through smoothly. Alternatively, you can use the webmail because it uses different protocol while sending emails than the email client e.g. outlook, thunderbird etc.
How to know your internet IP address?
You can go the following website in order to know your internet IP address.
https://www.whatismyip.com
How to see where my internet IP is blocked?
You can use online tools such as MX Toolbox, Spamhaus, or Barracuda Central to check your IP’s status.
https://mxtoolbox.com/blacklists.aspx
