Woocommerce integration problem after updating to 13.5.1

connection between woocommerce and erpnext worked - after updating to erpnext version 13.5.1 - getting these error logs:
in erpnext:
Traceback (most recent call last):
File “/home/ayers/frappe-bench/apps/erpnext/erpnext/erpnext_integrations/connectors/woocommerce_connection.py”, line 26, in order
_order(*args, **kwargs)
File “/home/ayers/frappe-bench/apps/erpnext/erpnext/erpnext_integrations/connectors/woocommerce_connection.py”, line 54, in _order
customer_name = raw_billing_data.get(“first_name”) + " " + raw_billing_data.get(“last_name”)
AttributeError: ‘NoneType’ object has no attribute ‘get’

Request Data:
{‘code’: ‘woocommerce_rest_cannot_view’, ‘message’: ‘Entschuldigung, du kannst diese Ressource nicht anzeigen.’, ‘data’: {‘status’: 401}}

woocommerce error log:

Body] => {\"code\":\"woocommerce_rest_cannot_view\",\"message\":\"Entschuldigung, du kannst diese Ressource nicht anzeigen.\",\"data\":{\"status\":401}}
        [Response] => Array
            (
                [Code] => 500
                [Message] => Internal Server Error
                [Headers] => Requests_Utility_CaseInsensitiveDictionary Object
                    (
                        [data:protected] => Array
                            (
                                [server] => nginx/1.10.3
                                [date] => Wed, 23 Jun 2021 07:16:14 GMT
                                [content-type] => application/json
                                [content-length] => 1194
                                [set-cookie] => Array
                                    (
                                        [0] => sid=Guest; Expires=Sat, 26-Jun-2021 09:16:14 GMT; HttpOnly; Path=/; SameSite=Lax
                                        [1] => system_user=no; Path=/; SameSite=Lax
                                        [2] => full_name=Guest; Path=/; SameSite=Lax
                                        [3] => user_id=Guest; Path=/; SameSite=Lax
                                        [4] => user_image=https%3A//secure.gravatar.com/avatar/adb831a7fdd83dd1e2a309ce7591dff8%3Fd%3Dretro; Path=/; SameSite=Lax
                                    )

                            )

                    )

                [Body] => {"exc":"[\"Traceback (most recent call last):\\n  File \\\"/home/ayers/frappe-bench/apps/frappe/frappe/app.py\\\", line 68, in application\\n    response = frappe.api.handle()\\n  File \\\"/home/ayers/frappe-bench/apps/frappe/frappe/api.py\\\", line 55, in handle\\n    return frappe.handler.handle()\\n  File \\\"/home/ayers/frappe-bench/apps/frappe/frappe/handler.py\\\", line 31, in handle\\n    data = execute_cmd(cmd)\\n  File \\\"/home/ayers/frappe-bench/apps/frappe/frappe/handler.py\\\", line 67, in execute_cmd\\n    return frappe.call(method, **frappe.form_dict)\\n  File \\\"/home/ayers/frappe-bench/apps/frappe/frappe/__init__.py\\\", line 1172, in call\\n    return fn(*args, **newargs)\\n  File \\\"/home/ayers/frappe-bench/apps/erpnext/erpnext/erpnext_integrations/connectors/woocommerce_connection.py\\\", line 26, in order\\n    _order(*args, **kwargs)\\n  File \\\"/home/ayers/frappe-bench/apps/erpnext/erpnext/erpnext_integrations/connectors/woocommerce_connection.py\\\", line 54, in _order\\n    customer_name = raw_billing_data.get(\\\"first_name\\\") + \\\" \\\" + raw_billing_data.get(\\\"last_name\\\")\\nAttributeError: 'NoneType' object has no attribute 'get'\\n\"]"}
            )

    )

)

any ideas? thanks in advance

It looks like woocommerce is not authorized to access ERPnext if that answers with 401. Check again the access token.