I appreciate tbe rich reponses to my question. I believe I found the answer. Not sure but at least the messages I've been sending now get to ter recipients
When I installed the operating systme, the host name some how at a numvber appended. I inteded to have nost name lenin, but it ended up lenin-16. When I discovred that afer installation I corrrected the host name in /etc/hsots and /etc/hostname. Whats I didn't check was what my router took to be my host name. It did not reponse to my changed host name and I had to do it manually in the router. Doing do seems to have solved my problem.