Calibre Memory error when sending emails

[jujuh]

Calibre 3.58.00 Windows 10 Enterprise 20H2, build 19042.1586

When trying to send "new" to my device over email, I get the below error.

Test Emails work fine, I've opened up the windows firewall

I've looked around and can't find anything.

Does anyone have any suggestions please

Spoiler:

---
calibre, version 5.38.0 (win32, embedded-python: True)
Failed to email book: Failed: Email The Daily Mail to aaa@bbb.com

Starting job: Email The Daily Mail to h*****@*****.com - Edited by me -
Waiting 301 seconds before sending, to avoid being marked as spam.
You can control this delay via Preferences->Tweaks
connect: ('mail.gmx.com', 587)
connect: to ('mail.gmx.com', 587) None
reply: b'220 gmx.net (mrgmx104) Nemesis ESMTP Service ready\r\n'
reply: retcode (220); Msg: b'gmx.net (mrgmx104) Nemesis ESMTP Service ready'
connect: b'gmx.net (mrgmx104) Nemesis ESMTP Service ready'
send: 'ehlo HP-Envy.bbb.internal\r\n'
reply: b'250-gmx.net Hello HP-Envy.bbb.internal [82.71.118.46]\r\n'
reply: b'250-8BITMIME\r\n'
reply: b'250-SIZE 69920427\r\n'
reply: b'250 STARTTLS\r\n'
reply: retcode (250); Msg: b'gmx.net Hello HP-Envy.bbb.internal [82.71.118.46]\n8BITMIME\nSIZE 69920427\nSTARTTLS'
send: 'STARTTLS\r\n'
reply: b'220 OK\r\n'
reply: retcode (220); Msg: b'OK'
send: 'ehlo HP-Envy.bbb.internal\r\n'
reply: b'250-gmx.net Hello HP-Envy.bbb.internal [82.71.118.46]\r\n'
reply: b'250-8BITMIME\r\n'
reply: b'250-AUTH LOGIN PLAIN\r\n'
reply: b'250 SIZE 69920427\r\n'
reply: retcode (250); Msg: b'gmx.net Hello HP-Envy.bbb.internal [82.71.118.46]\n8BITMIME\nAUTH LOGIN PLAIN\nSIZE 69920427'
send: AUTH <censored>
reply: b'235 Authentication succeeded\r\n'
reply: retcode (235); Msg: b'Authentication succeeded'
send: 'quit\r\n'
reply: b'221 gmx.net Service closing transmission channel\r\n'
reply: retcode (221); Msg: b'gmx.net Service closing transmission channel'

Sending failed...

Traceback (most recent call last):
File "calibre\gui2\email.py", line 48, in run
File "calibre\gui2\email.py", line 137, in sendmail
File "calibre\utils\smtp.py", line 184, in sendmail
File "smtplib.py", line 968, in send_message
File "email\generator.py", line 116, in flatten
File "email\generator.py", line 181, in _write
File "email\generator.py", line 214, in _dispatch
File "email\generator.py", line 272, in _handle_multipart
File "email\generator.py", line 116, in flatten
File "email\generator.py", line 181, in _write
File "email\generator.py", line 214, in _dispatch
File "email\generator.py", line 432, in _handle_text
File "email\generator.py", line 249, in _handle_text
File "email\generator.py", line 155, in _write_lines
File "email\generator.py", line 406, in write
MemoryError


Retrying in 301 seconds...

Waiting 301 seconds before sending, to avoid being marked as spam.
You can control this delay via Preferences->Tweaks

Sending failed...

Traceback (most recent call last):
File "calibre\gui2\email.py", line 48, in run
File "calibre\gui2\email.py", line 120, in sendmail
File "calibre\utils\smtp.py", line 271, in compose_mail
MemoryError

Job: "Email The Daily Mail to aaa@bbb.com" failed with error:
Traceback (most recent call last):
File "calibre\gui2\threaded_jobs.py", line 82, in start_work
File "calibre\gui2\email.py", line 105, in __call__
File "calibre\gui2\email.py", line 48, in run
File "calibre\gui2\email.py", line 120, in sendmail
File "calibre\utils\smtp.py", line 271, in compose_mail
MemoryError

Called with args: ('C:\\Users\\JULIAN~1.COL\\AppData\\Local\\Temp\\c alibre_zi6siiyc\\n5hx_r3gcaltmpfmt.mobi', 'The Daily Mail.mobi', 'aaa@bbb.com', 'News: The Daily Mail', 'Attached is the The Daily Mail periodical downloaded by calibre.') {'notifications': <queue.Queue object at 0x0FD6ED48>, 'abort': <threading.Event object at 0x0FD6EE80>, 'log': <calibre.utils.logging.GUILog object at 0x0FD6EEF8>}

[DNSB]

Are you running a 64 bit version of Windows 10? If so, you might want to try installing the 64 bit version of calibre.