How to fix "error in process filter..."

[Henry S. Greenside]

I am still struggling to get gnus 5.9.0 to talk to an
imap server via ssl.

When I tried these lines in my .gnus file:

    (setq gnus-secondary-select-methods '((nnfolder "")))
    (setq mail-sources '((imap :server "mail.phy.duke.edu"
       :port 993 :user "hsg" :stream ssl)))

and activate gnus, I get asked for my imap password but
then get the following error:

   error in process filter: Internal error, tag 5
   status BAD code nil text Bogus attribute list in UID
   Fetch

Anyone out there able to suggest what to do about this
error?

    Thanks,

    Henry