error sending emails via Yahoo! mail

[Eric S Fraga]

Hi,

with an up to date (from git) gnus, I get the following error whenever I
try to send an email via Yahoo! mail:

,----
| Debugger entered--Lisp error: (wrong-type-argument stringp nil)
| string-match("^[^:]+:" nil)
| nnimap-retrieve-group-data-early("yahoo" (nil))
| nnimap-request-group("Sent" "yahoo" t nil)
| gnus-request-group("nnimap+yahoo:Sent" t "nnimap:yahoo")
| gnus-inews-do-gcc()
| gnus-agent-possibly-do-gcc()
| run-hooks(message-sent-hook)
| message-send(nil)
| message-send-and-exit(nil)
| funcall-interactively(message-send-and-exit nil)
| call-interactively(message-send-and-exit nil nil)
| command-execute(message-send-and-exit)
`----

The email does get sent; it's the GCC element of sending that
fails. This has been happening for some time now. I seldom use Yahoo!
for sending emails so cannot be sure for how long, however.

What silly thing am I doing?

Thanks,
eric