My sister e-mailed me a few times and I am not receiving her e-mails. She has replied to some of my e-mails that I sent and I am not receiving them. My spouse is not receiving e-mails I am sending to him and my cousin receives my e-mails, replies to them and I am not receiving anything from her either. Could you please help me fix this so that I can receive their e-mails and so that others can receive mine?

It might be blocking software that blocks spam. You need to check your filter. It may be blocking your email by thinking they are spam and need your permission to proceed.