Error:
Odoo Server Error

Traceback (most recent call last):
  File "/usr/local/lib/python3.7/site-packages/odoo/http.py", line 619, in _handle_exception
    return super(JsonRequest, self)._handle_exception(exception)
  File "/usr/local/lib/python3.7/site-packages/odoo/http.py", line 309, in _handle_exception
    raise pycompat.reraise(type(exception), exception, sys.exc_info()[2])
  File "/usr/local/lib/python3.7/site-packages/odoo/tools/pycompat.py", line 14, in reraise
    raise value
  File "/usr/local/lib/python3.7/site-packages/odoo/http.py", line 664, in dispatch
    result = self._call_function(**self.params)
  File "/usr/local/lib/python3.7/site-packages/odoo/http.py", line 345, in _call_function
    return checked_call(self.db, *args, **kwargs)
  File "/usr/local/lib/python3.7/site-packages/odoo/service/model.py", line 93, in wrapper
    return f(dbname, *args, **kwargs)
  File "/usr/local/lib/python3.7/site-packages/odoo/http.py", line 338, in checked_call
    result = self.endpoint(*a, **kw)
  File "/usr/local/lib/python3.7/site-packages/odoo/http.py", line 910, in __call__
    return self.method(*args, **kw)
  File "/usr/local/lib/python3.7/site-packages/odoo/http.py", line 510, in response_wrap
    response = f(*args, **kw)
  File "/usr/local/lib/python3.7/site-packages/odoo/addons/web/controllers/main.py", line 1324, in call_button
    action = self._call_kw(model, method, args, kwargs)
  File "/usr/local/lib/python3.7/site-packages/odoo/addons/web/controllers/main.py", line 1312, in _call_kw
    return call_kw(request.env[model], method, args, kwargs)
  File "/usr/local/lib/python3.7/site-packages/odoo/api.py", line 395, in call_kw
    result = _call_kw_multi(method, model, args, kwargs)
  File "/usr/local/lib/python3.7/site-packages/odoo/api.py", line 382, in _call_kw_multi
    result = method(recs, *args, **kwargs)
  File "/var/lib/odoo/extra-addons/iterativo/l10n-dominicana/l10n_do_accounting/wizard/account_move_cancel.py", line 36, in move_cancel
    invoice.write({'state': 'cancel'})
  File "/usr/local/lib/python3.7/site-packages/odoo/addons/purchase/models/account_invoice.py", line 90, in write
    res = super(AccountMove, self).write(vals)
  File "/usr/local/lib/python3.7/site-packages/odoo/addons/account/models/account_move.py", line 1579, in write
    res = super(AccountMove, self.with_context(check_move_validity=False)).write(vals)
  File "/usr/local/lib/python3.7/site-packages/odoo/addons/mail/models/mail_thread.py", line 322, in write
    result = super(MailThread, self).write(values)
  File "/usr/local/lib/python3.7/site-packages/odoo/addons/mail/models/mail_activity.py", line 681, in write
    return super(MailActivityMixin, self).write(vals)
  File "/usr/local/lib/python3.7/site-packages/odoo/models.py", line 3551, in write
    real_recs._validate_fields(set(vals) - set(inverse_fields))
  File "/usr/local/lib/python3.7/site-packages/odoo/models.py", line 1167, in _validate_fields
    check(self)
  File "/var/lib/odoo/extra-addons/iterativo/l10n-dominicana/l10n_do_accounting/models/account_move.py", line 382, in _check_fiscal_purchase
    rec.partner_id.vat, l10n_latam_document_number
  File "/usr/local/lib/python3.7/site-packages/stdnum/do/ncf.py", line 176, in check_dgii
    validation = document.find('.//input[@name="__EVENTVALIDATION"]').get('value')
AttributeError: 'NoneType' object has no attribute 'get'