wifi connection and email question

Dear All,

I would welcome any help. I will try and be as clear as possible and I hope I posted on the right board.

1. I connect my macbook air to email via wifi at home.
2. When I do this I can send and receive emails using the mac email program
3. I can also connect to the internet as well.

Now the problem

1. When I am in a hotel say and connecting to the internet using a wifi hotspot:-
2. I can surf the internet with no issues
3. But cannot seem to send or receive any emails.

I also have a similar problem with my iphone except even at home I can't send any emails when wifi is on but it receives with no issues. Again, using a wifi hotspot I have the same issue. Turning off wifi and switching to 3g or edge I can receive and send emails.

Any ideas?

thanks

Josh