Administrator account produces error log entry every 4 minutes

When I log in to the Administrator account, in the error log is filled with reports:
{‘retry’: 0, ‘log’: <function log at 0x7f1d96d42140>, ‘site’: u’site1.local’, ‘event’: u’all’, ‘method_name’: u’frappe.email.queue.flush’, ‘method’: <function flush at 0x7f1d96290d70>, ‘user’: u’Administrator’, ‘kwargs’: {}, ‘async’: True, ‘job_name’: u’frappe.email.queue.flush’}
Traceback (most recent call last):
File “/home/admin/frappe-bench/apps/frappe/frappe/utils/background_jobs.py”, line 71, in execute_job
method(**kwargs)
File “/home/admin/frappe-bench/apps/frappe/frappe/email/queue.py”, line 324, in flush
check_email_limit([])
File “/home/admin/frappe-bench/apps/frappe/frappe/email/queue.py”, line 214, in check_email_limit
smtp_server = SMTPServer()
File “/home/admin/frappe-bench/apps/frappe/frappe/email/smtp.py”, line 137, in init
self.setup_email_account(append_to)
File “/home/admin/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/admin/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/admin/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/admin/frappe-bench/apps/frappe/frappe/model/base_document.py”, line 663, in get_password
return get_decrypted_password(self.doctype, self.name, fieldname, raise_exception=raise_exception)
File “/home/admin/frappe-bench/apps/frappe/frappe/utils/password.py”, line 16, in get_decrypted_password
return decrypt(auth[0][0])
File “/home/admin/frappe-bench/apps/frappe/frappe/utils/password.py”, line 106, in decrypt
frappe.throw(_(‘Encryption key is invalid, Please check site_config.json’))
File “/home/admin/frappe-bench/apps/frappe/frappe/init.py”, line 319, in throw
msgprint(msg, raise_exception=exc, title=title, indicator=‘red’)
File “/home/admin/frappe-bench/apps/frappe/frappe/init.py”, line 309, in msgprint
_raise_exception()
File “/home/admin/frappe-bench/apps/frappe/frappe/init.py”, line 282, in _raise_exception
raise raise_exception(encode(msg))
ValidationError: Encryption key is invalid, Please check site_config.json

It looks like Administrator attempt to send some email, and fails.
In the User list there is no email assigned to the administrator (In user details email is present, however it is not shown in list view):

@andrius when you restore a site, you also need to add the site’s encryption key, otherwise stored passwords will be unusable.

I have fresh install using the python script. The install went with errors, so I had to run script several times and generally, configure database user manually. It seems that install script has some issues - even if one provides all passwords, it might use some other password (from where it is getting it?).
I did downloaded site_config.json once install completed, however, it did not contain encryption key for some reason.
As somenone else suggested in forum, editing database directly and setting default_outgoing fields in tabEmailAccount table to “0”, and then reentering email domain info regenerated encryption key. Error messages stopped since then.
There is another issue though (not sure if I need to start another thread). Since last night I am not able to login as Administrator. Checked _Auth table and there is no such user. Is this normal? It seems somehow Administrator user dissapeared (I was able to login as Admin ~12 hours ago).

try bench --site [sitename] set-admin-password [password]

That fixed issue, thank you!