Using Mac Mail on a Public Server

I use a dial up ISP at home and I am able to send, receive and surf the internet without any problem. Now I am sitting in our public library that has wireless hi speed internet. I can surf the net and receive email but can not send any email using my Mac Mail App.

Problem: It says that my account through my ISP is offline. I have been playing with this for a while and can not seem to get it so that I can send mail using this Public Server. Is there a setting that has to be clicked to make this possible.

Someone told me a while ago that it has to do with authentication but I have tried every setting in the Mail preferences without success.

Any help would be appreciated.

 

Out in a rural section of PA. We ran a petition last year and will get High Speed DSL in December of this year. Can Not wait!

I will check with the library. Thank you for the response.