OPTION request - no answer from pbxes

Hello everybody,
my DID provider can't deliver the calls to pbxes since it appears that Pbxes doesn't always answer to the OPTION request my provider send.

For the most part of the day everything work fine, meaning that PBXES answer correctly.

These are the OPTION messages. The originating server expect a 200 OK as answer.

U 81.201.82.140:5080 -> 188.40.65.170:5060
OPTIONS sip:pbxes.org:5060 SIP/2.0.
Call-ID: b7bcd72f41356f0cda6df3916ada2727@81.201.82.140.
CSeq: 100 OPTIONS.
From: "Voxbone Monitoring" <sip:voxmon@81.201.82.140>;tag=2316.
To: <sip:pbxes.org:5060>.
Max-Forwards: 0.
Route: <sip:pbxes.org:5060>.
Via: SIP/2.0/UDP 81.201.82.140:5080;branch=z9hG4bK7aa5a73391d89f0377c81252196ebc15.
Content-Length: 0.
.

U 81.201.82.140:5080 -> 188.40.65.170:5060
OPTIONS sip:pbxes.org:5060 SIP/2.0.
Call-ID: b7bcd72f41356f0cda6df3916ada2727@81.201.82.140.
CSeq: 100 OPTIONS.
From: "Voxbone Monitoring" <sip:voxmon@81.201.82.140>;tag=2316.
To: <sip:pbxes.org:5060>.
Max-Forwards: 0.
Route: <sip:pbxes.org:5060>.
Via: SIP/2.0/UDP 81.201.82.140:5080;branch=z9hG4bK7aa5a73391d89f0377c81252196ebc15.
Content-Length: 0.
.

Any help is appreciated

RE: OPTION request - no answer from pbxes

It seems that this is not a bug but a configuration issue.

Pbxes accepts OPTION request only if you have a valid username in the "TO" field. for example this is a valid TO target

To: btwvoip@pbxes.org

and returns a 200 OK

while

To: pbxes.org
returns a timeout

I guess that the modification should be done on pbxes side, to solve your problem.
Hopefully they will make this change, since it would help all of their customers.