Solution is found:
compile project x86 only (not Any CPU)

When can I try to install and run my service with ALT.SMS on x64-base computer, I have this message:

Unhandled Exception: System.BadImageFormatException: Could not load file or assembly 'ALT.SMS.SmppClient, Version=2.6.7.0, Culture=neutral, PublicKeyToken=f4ef11ed003c8441' or one of its ...

Thanks. We will work in other coding.

Whether this error with an incorrect code will be corrected?

Thanks in advance.

I try to send the message containing an underscore, but it is transferred in the wrong coding.

Dim sm As SubmitSm
Dim Message as String = "test _ test"
sm = New SubmitSm
sm.Command = CommandSet.SubmitSm
sm.DataCoding = ALT.SMS.DataCodings.Default
sm.DestAddr = DestAddr
sm.DestNpi = Convert ...

I have same error.
"Too long Parameter name: S"

Stack Trace:
at wHcW8EeS8UMgjM9EFR.aEOKR878JGLThiP76W.qI9WackZg(String , Int32 )
at ALT.SMS.SubmitSm.suBHmnexr()
at ALT.SMS.SubmitSm.ALT.SMS.IPacket.GetBytes()
at ALT.SMS.SmppClient.KkdQHOPxF(IPacket )
at ALT.SMS.SmppClient.Submit(SubmitSm ...

Hello. I try to send a message with more than 130 chars (130-160 chars english text) but receive this error:

"Value was either too large or too small for an unsigned byte."

StackTrace:
at System.Convert.ToByte(Int32 value)
at ALT.SMS.SubmitSm.suBHmnexr()
at ALT.SMS.SubmitSm.ALT.SMS.IPacket ...