Mail app does not collect my emails from my server?

I have a Mac operating system 10.9.5

For quite sometime I am having trouble with my Mail App.

I have a mail account with talk talk.net

I always make sure that i am putting the correct password

Despite this I continually get the message : Internet Account preferences can't connect to account "TalkTalk"

Password could not be sent to "mail.talktalk.net" securely

You can continue without a password, which could put your password at risk.

I have re-set my mail account.

This has not helped.

Now my mail app does not collect my mail from my server taltalk.net.

I have rung my sever & have checked all the setting for the talk talk accout, but this hs not helped.

I shall be happy if someone can help me with this issue with my Mail app.