Can anyone help this novice with this error message?

[cutig...@gmail.com]

I am using Mail Server, v. 1.3.4.0 with Windows 10 Pro. 

We get the following error message when emailing to one of our clients:

ERROR: One or more errors occurred.. Inner exception: Timeout when waiting from data. System.AggregateException

Is there anything I need to do? Or, is it the client's email server?

Thanks,

Scott

[ArGoSoft Products]

Well...  It means timeout. Someone was trying to connect to you, or you were trying to connect to it, and at some stage connection got "stuck" and timed out.