Optimum is my mail server

I do not have Optimum I have comcast.  So this may or may not work.

Enter it as a new POP account. 

Enter in user name and password then select manual set up

then for pop server type    mail.(whatever your ending email address is IE: optimum.com)
security none
server 110
then click next
for smpt server type smpt.(whatever your ending email address is IE: optimum.com)
security none.


Give this a try and see if it helps.