May anyone help in solving this error:

Odoo Server Error

Traceback (most recent call last):
  File "/usr/lib/python3/dist-packages/odoo/tools/cache.py", line 85, in lookup
    r = d [key]
  File "/usr/lib/python3/dist-packages/odoo/tools/func.py", line 69, in wrapper
    return func (self, * args, ** kwargs)
  File "/usr/lib/python3/dist-packages/odoo/tools/lru.py", line 44, in __getitem__
    a = self.d [obj] .me
KeyError: ('ir.ui.view', <function View.get_view_id at 0x7f7624504378>, 2, False, 'res.partner.report_res_partner', (None,))

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/usr/lib/python3/dist-packages/odoo/tools/cache.py", line 85, in lookup
    r = d [key]
  File "/usr/lib/python3/dist-packages/odoo/tools/func.py", line 69, in wrapper
    return func (self, * args, ** kwargs)
  File "/usr/lib/python3/dist-packages/odoo/tools/lru.py", line 44, in __getitem__
    a = self.d [obj] .me
KeyError: ('ir.model.data', <function IrModelData.xmlid_lookup at 0x7f7627febc80>, 'res.partner.report_res_partner')

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/usr/lib/python3/dist-packages/odoo/addons/web/controllers/main.py", line 2034, in report_download
    response = self.report_routes (reportname, docids = docids, converter = converter, context = context)
  File "/usr/lib/python3/dist-packages/odoo/http.py", line 515, in response_wrap
    response = f (* args, ** kw)
  File "/home/ubuntu/mymodules/report_xlsx/controllers/main.py", line 49, in report_routes
    reportname, docids, converter, ** data
  File "/usr/lib/python3/dist-packages/odoo/http.py", line 515, in response_wrap
    response = f (* args, ** kw)
  File "/usr/lib/python3/dist-packages/odoo/addons/web/controllers/main.py", line 1972, in report_routes
    pdf = report.with_context (context) .render_qweb_pdf (docids, data = data) [0]
  File "/usr/lib/python3/dist-packages/odoo/addons/base/models/ir_actions_report.py", line 737, in render_qweb_pdf
    html = self.with_context (context) .render_qweb_html (res_ids, data = data) [0]
  File "/usr/lib/python3/dist-packages/odoo/addons/base/models/ir_actions_report.py", line 777, in render_qweb_html
    return self.render_template (self.report_name, data), 'html'
  File "/usr/lib/python3/dist-packages/odoo/addons/base/models/ir_actions_report.py", line 548, in render_template
    return view_obj.render_template (template, values)
  File "/usr/lib/python3/dist-packages/odoo/addons/base/models/ir_ui_view.py", line 1191, in render_template
    return self.browse (self.get_view_id (template)). render (values, engine)
  File "<decorator-gen-186>", line 2, in get_view_id
  File "/usr/lib/python3/dist-packages/odoo/tools/cache.py", line 90, in lookup
    value = d [key] = self.method (* args, ** kwargs)
  File "/usr/lib/python3/dist-packages/odoo/addons/website/models/ir_ui_view.py", line 299, in get_view_id
    return super (View, self) .get_view_id (xml_id)
  File "/usr/lib/python3/dist-packages/odoo/addons/base/models/ir_ui_view.py", line 1087, in get_view_id
    return view and view.id or self.env ['ir.model.data']. xmlid_to_res_id (template, raise_if_not_found = True)
  File "/usr/lib/python3/dist-packages/odoo/addons/base/models/ir_model.py", line 1694, in xmlid_to_res_id
    return self.xmlid_to_res_model_res_id (xmlid, raise_if_not_found) [1]
  File "/usr/lib/python3/dist-packages/odoo/addons/base/models/ir_model.py", line 1685, in xmlid_to_res_model_res_id
    return self.xmlid_lookup (xmlid) [1: 3]
  File "<decorator-gen-24>", line 2, in xmlid_lookup
  File "/usr/lib/python3/dist-packages/odoo/tools/cache.py", line 90, in lookup
    value = d [key] = self.method (* args, ** kwargs)
  File "/usr/lib/python3/dist-packages/odoo/addons/base/models/ir_model.py", line 1674, in xmlid_lookup
    raise ValueError ('External ID not found in the system:% s'% xmlid)
ValueError: External ID not found in the system: res.partner.report_res_partner

This is my view code:

<? xml version = "1.0" encoding = "utf-8"?>

<odoo>

    <data>

        <template id = "report_res_partner">

            <t t-call = "report.external_layout">

                <t t-foreach = "received_data" t-as = "doc">

                    <div class = "page">

                        <div class = "oe_structure" />

                        <html>

                            <head>

                                <link rel = "stylesheet" href = "https://fonts.googleapis.com/css?family=Droid Arabic Kufi" />

                                <style>

                                    body{

                                        font-family: 'Droid Arabic Kufi', 'serif',

                                        ffont-size: 14px

                                    }

                                </style>

                            </head>

                            <body>

                                <div />

                            </body>

                        </html>

                        <div style = "float: right, width: 48%" DIR = "RTL">

                            <p>

                                <span> الساده / </span>

                                <br/>

                                <br/>

                                <span> التاريخ <t t-esc = "doc.date" /> </span>

                            </p>

                        </div>

                    </div>

                </t>

            </t>

        </template>

    </data>

</odoo>

And here is the other code:

<? xml version = "1.0" encoding = "utf-8"?>

<odoo>

    <data>

        <! - QWeb Reports ->

        <! - NAME & FILE_NAME should be the same ->

                <postponement

                    id = "res_partner_report"

                    model = "res.partner"

                    report_type = "qweb-pdf"

                    string = "Client Authentication"

                    name = "res.partner.report_res_partner"

                    file = "res.partner.report_res_partner"

                />

    </data>

</odoo>