Frappe server ERROR: frappe.exceptions.ValidationError: Expecting value: line 1 column 1 (char 0)

The error occurs since the system is in production. It used to happen once a day, but lately it happens every hour.
When the service was in testing, the error used to occur when the server was shut down and it was enough to restart it. But now, I don’t know what could be the problem. Any advice will be helpful.

Traceback (most recent call last):
  File "apps/frappe/frappe/", line 69, in application
    response = frappe.api.handle()
  File "apps/frappe/frappe/", line 55, in handle
    return frappe.handler.handle()
  File "apps/frappe/frappe/", line 38, in handle
    data = execute_cmd(cmd)
  File "apps/frappe/frappe/", line 76, in execute_cmd
    return, **frappe.form_dict)
  File "apps/frappe/frappe/", line 1457, in call
    return fn(*args, **newargs)
  File "apps/frappe/frappe/desk/form/", line 22, in savedocs
  File "apps/frappe/frappe/model/", line 1018, in submit
    return self._submit()
  File "apps/frappe/frappe/model/", line 1007, in _submit
  File "apps/frappe/frappe/model/", line 310, in save
    return self._save(*args, **kwargs)
  File "apps/frappe/frappe/model/", line 347, in _save
  File "apps/frappe/frappe/model/", line 1055, in run_before_save_methods
  File "apps/frappe/frappe/model/", line 941, in run_method
    out = Document.hook(fn)(self, *args, **kwargs)
  File "apps/frappe/frappe/model/", line 1259, in composer
    return composed(self, method, *args, **kwargs)
  File "apps/frappe/frappe/model/", line 1241, in runner
    add_to_return_value(self, fn(self, *args, **kwargs))
  File "apps/frappe/frappe/model/", line 938, in fn
    return method_object(*args, **kwargs)
  File "apps/electronic_billing/electronic_billing/electronic_billing/doctype/sales_invoice/", line 70, in validate
  File "apps/frappe/frappe/", line 504, in throw
  File "apps/frappe/frappe/", line 479, in msgprint
  File "apps/frappe/frappe/", line 434, in _raise_exception
    raise raise_exception(msg)
frappe.exceptions.ValidationError: Expecting value: line 1 column 1 (char 0)

Frappe Framework: v13.22.0 (version-13)