[Users] Difficulty sending through Gmail

[Liz]

I have suddenly had changes in my ability to send mail out using Google
SMTP server.
Debian Stretch/Sid
Claws Mail 3.14.0
Probably commenced after some updates to install "Wine".
No change on the Gmail side to my account.
I can receive mail from Gmail as usual.
No encryption involved.
The mail appears in the Queue list on Gmail (web interface) but doesn't
get sent.

Can somebody advise where I should look?
Liz
(sending this through an alternate mail server)



Log shows
[11:01:11] IMAP4> 6924 NOOP 
[11:01:12] IMAP4< 6924 OK Success 
[11:01:26] IMAP4> 6925 SELECT "[Gmail]/Queue" 
[11:01:26] IMAP4< * FLAGS (\Answered \Flagged \Draft \Deleted \Seen
$Forwarded $NotPhishing $Phishing Junk NonJunk) [11:01:26] IMAP4< * OK
[PERMANENTFLAGS (\Answered \Flagged \Draft \Deleted \Seen $Forwarded
$NotPhishing $Phishing Junk NonJunk \*)] Flags permitted. [11:01:26]
IMAP4< * OK [UIDVALIDITY 656286474] UIDs valid. [11:01:26] IMAP4< * 0
EXISTS [11:01:26] IMAP4< * 0 RECENT [11:01:26] IMAP4< * OK [UIDNEXT
2402] Predicted next UID. [11:01:26] IMAP4< * OK [HIGHESTMODSEQ
3935837] [11:01:26] IMAP4< 6925 OK [READ-WRITE] [Gmail]/Queue selected.
(Success) [11:01:26] IMAP4- [fetching UIDs...]
[11:01:26] IMAP4> 6926 UID FETCH 1:* (UID) 
[11:01:27] IMAP4< 6926 OK Success 
[11:01:27] IMAP4> 6927 APPEND "[Gmail]/Queue" (\Seen) {629} 
[11:01:27] IMAP4< + go ahead 
[11:01:27] IMAP4> [data - 631 bytes]
[11:01:28] IMAP4< * 1 EXISTS 
[11:01:28] IMAP4< 6927 OK [APPENDUID 656286474 2402] (Success) 
[11:01:28] IMAP4> 605 NOOP 
[11:01:28] IMAP4< 605 OK NOOP completed. 
[11:01:28] IMAP4> 249 NOOP 
[11:01:28] IMAP4< 249 OK NOOP completed. 
[11:01:28] IMAP4> 277 NOOP 
[11:01:28] IMAP4< 277 OK NOOP completed. 
[11:01:28] IMAP4> 228 NOOP 
[11:01:28] IMAP4< 228 OK NOOP completed. 
[11:01:28] IMAP4> 6928 NOOP 
[11:01:29] IMAP4< 6928 OK Success 
[11:01:29] IMAP4> 6929 UID STORE 2402 +FLAGS.SILENT (\Seen) 
[11:01:30] IMAP4< 6929 OK Success 
* Account 'Gmail': Connecting to SMTP server: smtp.gmail.com:25...
[11:02:12] IMAP4> 6930 NOOP 
[11:02:13] IMAP4< 6930 OK Success 
[11:02:28] IMAP4> 606 NOOP 
[11:02:28] IMAP4< * 241 EXISTS 
[11:02:28] IMAP4< * 5 RECENT 
[11:02:28] IMAP4< 606 OK NOOP completed. 
[11:02:28] IMAP4> 250 NOOP 
[11:02:28] IMAP4< 250 OK NOOP completed. 
[11:02:28] IMAP4> 278 NOOP 
[11:02:29] IMAP4< 278 OK NOOP completed. 
[11:02:29] IMAP4> 229 NOOP 
[11:02:29] IMAP4< 229 OK NOOP completed. 
*** Session timed out. You may be able to recover by increasing the
timeout value in Preferences/Other/Miscellaneous. [11:02:30] IMAP4>
6931 UID STORE 2402 +FLAGS.SILENT (\Deleted) [11:02:31] IMAP4< * 1
EXPUNGE [11:02:31] IMAP4< * 0 EXISTS 
[11:02:31] IMAP4< 6931 OK S
[11:02:31] IMAP4< uccess 
[11:02:31] IMAP4> 6932 EXPUNGE 
[11:02:32] IMAP4< 6932 OK Success 
[11:02:32] IMAP4- [fetching UIDs...]
[11:02:32] IMAP4> 6933 UID FETCH 1:* (UID) 
[11:02:32] IMAP4< 6933 OK Success