Error when Saving E-Mail Account or Trying to send

I get this error when I want to save the eMail account and send email. What does this mean:

{‘retry’: 0, ‘log’: <function log at 0x7fdee407a230>, ‘site’: u’example.com’, ‘event’: u’all’, ‘method_name’: u’frappe.email.queue.flush’, ‘method’: <function flush at 0x7fdee3fc30c8>, ‘user’: u’Administrator’, ‘kwargs’: {}, ‘async’: True, ‘job_name’: u’frappe.email.queue.flush’}
Traceback (most recent call last):
File “/home/emin/frappe-bench/apps/frappe/frappe/utils/background_jobs.py”, line 65, in execute_job
method(**kwargs)
File “/home/emin/frappe-bench/apps/frappe/frappe/email/queue.py”, line 282, in flush
check_email_limit([])
File “/home/emin/frappe-bench/apps/frappe/frappe/email/queue.py”, line 189, in check_email_limit
smtp_server = SMTPServer()
File “/home/emin/frappe-bench/apps/frappe/frappe/email/smtp.py”, line 137, in init
self.setup_email_account(append_to)
File “/home/emin/frappe-bench/apps/frappe/frappe/email/smtp.py”, line 140, in setup_email_account
self.email_account = get_outgoing_email_account(raise_exception_not_set=False, append_to=append_to)
File “/home/emin/frappe-bench/apps/frappe/frappe/email/smtp.py”, line 54, in get_outgoing_email_account
email_account = get_default_outgoing_email_account(raise_exception_not_set=raise_exception_not_set)
File “/home/emin/frappe-bench/apps/frappe/frappe/email/smtp.py”, line 87, in get_default_outgoing_email_account
email_account.password = email_account.get_password(raise_exception=False)
File “/home/emin/frappe-bench/apps/frappe/frappe/model/base_document.py”, line 665, in get_password
return get_decrypted_password(self.doctype, self.name, fieldname, raise_exception=raise_exception)
File “/home/emin/frappe-bench/apps/frappe/frappe/utils/password.py”, line 16, in get_decrypted_password
return decrypt(auth[0][0])
File “/home/emin/frappe-bench/apps/frappe/frappe/utils/password.py”, line 101, in decrypt
cipher_suite = Fernet(encode(get_encryption_key()))
File “/home/emin/frappe-bench/env/local/lib/python2.7/site-packages/cryptography/fernet.py”, line 37, in init
“Fernet key must be 32 url-safe base64-encoded bytes.”
ValueError: Fernet key must be 32 url-safe base64-encoded bytes.

@pronext
Would you mind sharing more details like which version you are on and integrations if any.

ERPNext: v8.0.48 (master)

Frappe Framework: v8.0.66 (master)

No Integrations

Please provide solution to this problem