[Fetchmail-users] problem after upgrade to Ubuntu 19.10

[<ric...@bt...>]

I have just upgraded from Ubuntu 19.04 to 19.10 and I find that 
fetchmail is unable to retrieve emails from the POP3 server. The log 
suggests it's an SSL problem, but I don't have the technical knowledge 
to fix it.  The log says:

fetchmail: Query status=2 (SOCKET)
fetchmail: awakened by User defined signal 1
fetchmail: starting fetchmail 6.4.0.rc4 daemon
fetchmail: mail.btinternet.com: upgrade to TLS failed.
fetchmail: Unknown login or authentication error on 
<user>@bti...@ma...
fetchmail: socket error while fetching from 
<user>@bti...@ma...
fetchmail: Query status=2 (SOCKET)

I gather that my provider supports ssl but not startttls, but I have no 
idea what that means.

I'd really appreciate some guidance on what to do.

- Richard