When sending out an invitation on the server I created I get the following errors. I'm learning how to configure odoo so would greatly appreciate advice. 

Traceback (most recent call last):
  File "/opt/odoo16/odoo/addons/base/models/ir_mail_server.py", line 695, in send_email
    smtp.send_message(message, smtp_from, smtp_to_list)
  File "/usr/lib/python3.8/smtplib.py", line 979, in send_message
    return self.sendmail(from_addr, to_addrs, flatmsg, mail_options,
  File "/usr/lib/python3.8/smtplib.py", line 894, in sendmail
    raise SMTPRecipientsRefused(senderrs)
smtplib.SMTPRecipientsRefused: {'admin@triplepointinnovation.co.za': (550, b'Verification failed for \nSender verify failed')}

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/opt/odoo16/odoo/http.py", line 1584, in _serve_db
    return service_model.retrying(self._serve_ir_http, self.env)
  File "/opt/odoo16/odoo/service/model.py", line 134, in retrying
    result = func()
  File "/opt/odoo16/odoo/http.py", line 1611, in _serve_ir_http
    response = self.dispatcher.dispatch(rule.endpoint, args)
  File "/opt/odoo16/odoo/http.py", line 1808, in dispatch
    result = self.request.registry['ir.http']._dispatch(endpoint)
  File "/opt/odoo16/addons/website/models/ir_http.py", line 235, in _dispatch
    response = super()._dispatch(endpoint)
  File "/opt/odoo16/odoo/addons/base/models/ir_http.py", line 149, in _dispatch
    result = endpoint(**request.params)
  File "/opt/odoo16/odoo/http.py", line 699, in route_wrapper
    result = endpoint(self, *args, **params_ok)
  File "/opt/odoo16/addons/web/controllers/dataset.py", line 46, in call_button
    action = self._call_kw(model, method, args, kwargs)
  File "/opt/odoo16/addons/web/controllers/dataset.py", line 33, in _call_kw
    return call_kw(request.env[model], method, args, kwargs)
  File "/opt/odoo16/odoo/api.py", line 461, in call_kw
    result = _call_kw_multi(method, model, args, kwargs)
  File "/opt/odoo16/odoo/api.py", line 448, in _call_kw_multi
    result = method(recs, *args, **kwargs)
  File "/opt/odoo16/addons/auth_signup/models/res_users.py", line 203, in action_reset_password
    template.send_mail(user.id, force_send=force_send, raise_exception=True, email_values=email_values)
  File "/opt/odoo16/addons/mail/models/mail_template.py", line 402, in send_mail
    mail.send(raise_exception=raise_exception)
  File "/opt/odoo16/addons/mail/models/mail_mail.py", line 413, in send
    self.browse(batch_ids)._send(
  File "/opt/odoo16/addons/mail/models/mail_mail.py", line 519, in _send
    res = IrMailServer.send_email(
  File "/opt/odoo16/odoo/addons/base/models/ir_mail_server.py", line 706, in send_email
    raise MailDeliveryException(_("Mail Delivery Failed"), msg)
odoo.addons.base.models.ir_mail_server.MailDeliveryException: ('Mail Delivery Failed', "Mail delivery failed via SMTP server 'None'.\nSMTPRecipientsRefused: {'admin@triplepointinnovation.co.za': (550, b'Verification failed for \\nSender verify failed')}")

The above server error caused the following client error:
RPC_ERROR: Odoo Server Error
    RPCError@https://www.triplepointinnovation.co.za/web/assets/debug/web.assets_backend.js:10165:9 (/web/static/src/core/network/rpc_service.js:11)
    makeErrorFromResponse@https://www.triplepointinnovation.co.za/web/assets/debug/web.assets_backend.js:10188:19 (/web/static/src/core/network/rpc_service.js:34)
    jsonrpc/promise