Let's Encrypt and "strange" tcp connections

Hello, I have let's encrypt for cPanel SSL for my cPanel users. I check (about 1 week now) the connections of my server and I see connections to akamaitechnologies from Ip's that seems (as I search) that are from Let's Encrypt. Yesterday I receive a message from my CSF firewall for a temporary block for [CT_LIMIT] reason of an IP that made 551 TCP connections... I search the IP and I fount it