Check Vies: Server raised fault: '{ 'Check Vies: Server raised fault: '{ 'MS_MAX_CONCURRENT_REQ' }' }'

Got this error today on "Check VIES":

Traceback (most recent call last):
  File "/usr/lib/python3.9/site-packages/trytond/protocols/dispatcher.py", line 180, in _dispatch
    result = rpc.result(meth(cargs, c_kwargs))
  File "/usr/lib/python3.9/site-packages/trytond/wizard/wizard.py", line 314, in execute
    return wizard._execute(state_name)
  File "/usr/lib/python3.9/site-packages/trytond/wizard/wizard.py", line 345, in _execute
    result = self._execute(transition())
  File "/usr/lib/python3.9/site-packages/trytond/modules/party/party.py", line 734, in transition_check
    if not eu_vat.check_vies(identifier.code)['valid']:
  File "/usr/lib/python3.9/site-packages/stdnum/eu/vat.py", line 132, in check_vies
    return client.checkVat(number[:2], number[2:])
  File "/usr/lib/python3.9/site-packages/zeep/proxy.py", line 40, in call
    return self._proxy._binding.send(
  File "/usr/lib/python3.9/site-packages/zeep/wsdl/bindings/soap.py", line 130, in send
    return self.process_reply(client, operation_obj, response)
  File "/usr/lib/python3.9/site-packages/zeep/wsdl/bindings/soap.py", line 195, in process_reply
    return self.process_error(doc, operation)
  File "/usr/lib/python3.9/site-packages/zeep/wsdl/bindings/soap.py", line 295, in process_error
    raise Fault(
zeep.exceptions.Fault: MS_MAX_CONCURRENT_REQ

probably just a new Error that needs to be added to the exception handling: http://hg.tryton.org/modules/party/file/c4be78ba02d0/party.py#l441 (can'd make a patch now, but it should be just a one-liner anyway so ..)