PHP Request Shutdown: Must use comma to separate addresses: Keßler | Proselection (errflg=3) [in Unknown, line 0]

I've got this message while I'm reading this object

```
object(greeny\MailLibrary\Contact) id:0 
{
     private mailbox => 'Nils'
     private host => 'UNKNOWN_HOST'
     private personal => null
     private adl => null
}
```

How to avoid errors like this?

Thanks a lot.

Michael