Hi Nhat, We had major problems with Apollo and got our domain blacklisted because their suggested email limit was too high. We are not using seamelss.ai which is a better database that is updated weekly on Sundays with Ai. We like it much better than Apollo which is very difficult to use. If you are interested in checking out Seamless.AI please let me know and I will connect you with our rep, Matthew Brines, who is great. Their support is killer. They did a zoom meeting with me the same day as my request for support. I have negotiated a deal with them that Matthew says that he can offer anyone I refer to him, without any referral fee. So I am not suggesting it for financial reasons at all. I just love referring people to good services. Best no matter what you do.