Can you find the response in the library log with the same sequence?
I mean the log event starting with "PDU Received:"

Do you use Wait() or .Result for Async methods?

After waiting for 6 minutes, it still didn't end

Is the ResponseTimeout longer than 6 minutes in your application? If the response is not received within this time, the library should generate a response with the status SMPPCLIENT_RCVTIMEOUT.

Hi aordonez,

Is library logging is enabled in your application? Could you send me at least ERROR and WARN log records?

CUAP ( China Mobile USSD Application Protocol ) is HTTP-based protocol.
Inetlab.SMPP doesn't support this.

Is CUAP based on SMPP protocol?

Hi jeremih

You cannot add optional TLV parameters to the Bind request, the SMPP protocol doesn't support this.

Why do you want to add the headers ?

Hi,

USSD over SMPP is always vendor specific implementation. Try to start with the sample USSD project.

It is already released. See the change log.

Please try to force the thread pool to create more worker threads

ok. submit speed 0 is the same as NoLimit in the SmppClientDemo.

Unfortunately I cannot reproduce this issue with latest version. Could you help me?
What server are you connecting? Can you reproduce this issue with SmppServerDemo?

Hello ritik,

When you set 0 for SendSpeedLimit property, do you want to disable this limit?
Have you tried LimitRate.NoLimit value?

I'll try to reproduce this case and let you know about results.

What library version do you use?

for example:

If SmppClient instance is not subscribed to evDeliverSm event the ESME_RINVCMDID will be returned.
If the handler of the event evDeliverSm is failed the ESME_RSYSERR will be returned and the error is written into the library log

You can always use try catch in the event handler method to handle ...

The smpp session will be dropped when unsuccess response status in EnquireLink is received.

In your case the server could be busy with your messages and the EnquireLinkResp is sent later than 19 seconds. The library already processed the timeout and returned the SMPPCLIENT_RCVTIMEOUT.

The detailed ...

What value have you set for the property ResponseTimeout in SmppClient instance?

The EnquireLink PDU is sent only in idle time. It means it will be sent in 20 seconds after last received PDU from the remote side.

Could you provide more detailed logs?