Why am I able to open up the Internet but not use Emails?

[Brian M. Leahy]

I'm in a Motor Caravan on the IOW on a site which although I paid a hefty fee to stay on then asked for more money to use their Wifi which I declined. Tight, possibly but I resented that charge in the smae way I resented the attempt of a local pub to charge me in excess of £6.00 for a pint so I went to the Coop and bought it there. Now to my question.
I'm able to access the Internet on my laptop and even access Facebook and comment. I'm also able to receive an Email but not able to send a reply. My smart phone works so could someone please enlighten a not very technically minded person why the problem with Email?

 

[Brian M. Leahy]

I have no idea why I'm able to connect to the internet without paying the ransom. I do use Thunderbird. When I attempt to send an Email the following comes up. "Connection to mail.com Sending of message failed. The message could not be sent because the connection to outgoing service SMTP mail.btinternet.com was lost in the middle of the transaction. As it is I'm off down to Freshwater where there is a very nice coffee place with WiFi to send my Email replies but I find the on site Email conundrum interesting. Is there such a thing as G4 systems for Laptops?