Unexplained mutt error

[Ion]

Since my previous attempts failed I decided to go the default route
using Fastmail IMAP and SMTP as advised on their web help page. I set my
.muttrc file as follows, hoping it would be easier to resolve the problem.

set imap_user=ionmich at eml.cc
set imap_pass="my fastmail password"
set realname    ="Ion"
set from = "ionmich at eml.cc"
set folder=imaps://imap.fastmail.com:993
set smtp_url ="smtp://smtp.fastmail.com:465"
set smtp_pass = "my fastmail password"
set ssl_force_tls =yes
set header_cache = ~/.cache/mutt
set spoolfile = "+INBOX"
set record ="+Sent Items"
set postponed="+Drafts"
set trash = "+Trash"
set editor ="nano"
set timeout=15
set mail_check=1
set check_new=yes
auto_view text/html

But the response was...

"SMTP session failed: read error"