Dear community,

In an attempt to try to modify the standard "Invoice" template using Studio on the web version of Odoo, I accidentally did alter the settings of the standard invoice template. While I can still generate the pdf invoices using the "print" function, the "preview" function stopped working, and I receive the error message below. 

Anyone any idea how this can be resolved/fixed?

Many thanks!

Traceback (most recent call last):
  File "/home/odoo/src/odoo/14.0/odoo/addons/base/models/ir_http.py", line 237, in _dispatch
    result = request.dispatch()
  File "/home/odoo/src/odoo/14.0/odoo/http.py", line 807, in dispatch
    r = self._call_function(**self.params)
  File "/home/odoo/src/odoo/14.0/odoo/http.py", line 360, in _call_function
    return checked_call(self.db, *args, **kwargs)
  File "/home/odoo/src/odoo/14.0/odoo/service/model.py", line 94, in wrapper
    return f(dbname, *args, **kwargs)
  File "/home/odoo/src/odoo/14.0/odoo/http.py", line 348, in checked_call
    result = self.endpoint(*a, **kw)
  File "/home/odoo/src/odoo/14.0/odoo/http.py", line 913, in __call__
    return self.method(*args, **kw)
  File "/home/odoo/src/odoo/14.0/odoo/http.py", line 532, in response_wrap
    response = f(*args, **kw)
  File "/home/odoo/src/odoo/14.0/addons/account/controllers/portal.py", line 99, in portal_my_invoice_detail
    return self._show_report(model=invoice_sudo, report_type=report_type, report_ref='account.account_invoices', download=download)
  File "/home/odoo/src/odoo/14.0/addons/portal/controllers/portal.py", line 408, in _show_report
    report_sudo = request.env.ref(report_ref).with_user(SUPERUSER_ID)
  File "/home/odoo/src/odoo/14.0/odoo/api.py", line 511, in ref
    return self['ir.model.data'].xmlid_to_object(xml_id, raise_if_not_found=raise_if_not_found)
  File "/home/odoo/src/odoo/14.0/odoo/addons/base/models/ir_model.py", line 1944, in xmlid_to_object
    t = self.xmlid_to_res_model_res_id(xmlid, raise_if_not_found)
  File "/home/odoo/src/odoo/14.0/odoo/addons/base/models/ir_model.py", line 1928, in xmlid_to_res_model_res_id
    return self.xmlid_lookup(xmlid)[1:3]
  File "", line 2, in xmlid_lookup
  File "/home/odoo/src/odoo/14.0/odoo/tools/cache.py", line 90, in lookup
    value = d[key] = self.method(*args, **kwargs)
  File "/home/odoo/src/odoo/14.0/odoo/addons/base/models/ir_model.py", line 1921, in xmlid_lookup
    raise ValueError('External ID not found in the system: %s' % xmlid)
Exception

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "/home/odoo/src/odoo/14.0/odoo/addons/base/models/ir_http.py", line 237, in _dispatch
    result = request.dispatch()
  File "/home/odoo/src/odoo/14.0/odoo/http.py", line 807, in dispatch
    r = self._call_function(**self.params)
  File "/home/odoo/src/odoo/14.0/odoo/http.py", line 360, in _call_function
    return checked_call(self.db, *args, **kwargs)
  File "/home/odoo/src/odoo/14.0/odoo/service/model.py", line 94, in wrapper
    return f(dbname, *args, **kwargs)
  File "/home/odoo/src/odoo/14.0/odoo/http.py", line 348, in checked_call
    result = self.endpoint(*a, **kw)
  File "/home/odoo/src/odoo/14.0/odoo/http.py", line 913, in __call__
    return self.method(*args, **kw)
  File "/home/odoo/src/odoo/14.0/odoo/http.py", line 532, in response_wrap
    response = f(*args, **kw)
  File "/home/odoo/src/odoo/14.0/addons/account/controllers/portal.py", line 99, in portal_my_invoice_detail
    return self._show_report(model=invoice_sudo, report_type=report_type, report_ref='account.account_invoices', download=download)
  File "/home/odoo/src/odoo/14.0/addons/portal/controllers/portal.py", line 408, in _show_report
    report_sudo = request.env.ref(report_ref).with_user(SUPERUSER_ID)
  File "/home/odoo/src/odoo/14.0/odoo/api.py", line 511, in ref
    return self['ir.model.data'].xmlid_to_object(xml_id, raise_if_not_found=raise_if_not_found)
  File "/home/odoo/src/odoo/14.0/odoo/addons/base/models/ir_model.py", line 1944, in xmlid_to_object
    t = self.xmlid_to_res_model_res_id(xmlid, raise_if_not_found)
  File "/home/odoo/src/odoo/14.0/odoo/addons/base/models/ir_model.py", line 1928, in xmlid_to_res_model_res_id
    return self.xmlid_lookup(xmlid)[1:3]
  File "", line 2, in xmlid_lookup
  File "/home/odoo/src/odoo/14.0/odoo/tools/cache.py", line 90, in lookup
    value = d[key] = self.method(*args, **kwargs)
  File "/home/odoo/src/odoo/14.0/odoo/addons/base/models/ir_model.py", line 1921, in xmlid_lookup
    raise ValueError('External ID not found in the system: %s' % xmlid)
ValueError: External ID not found in the system: account.account_invoices