Fix sendArtifacts method to use the correct Serder subclass for TEL events.

src/keri/core/serdering.py

@@ -433,7 +433,7 @@ def __init__(self, *, raw=b'', sad=None, strip=False, version=Version,
                     logger.error("Invalid raw for Serder %s\n%s",
                                  self.pretty(), ex.args[0])
                     raise ValidationError(f"Invalid raw for Serder = "
-                                          f"{self._sad}.") from ex
+                                          f"{self._sad}. {ex.args[0]}") from ex
 
         elif sad or makify:  # serialize sad into raw or make sad
             if makify:  # recompute properties and said(s) and reset sad

src/keri/peer/exchanging.py

@@ -76,8 +76,8 @@ def processEvent(self, serder, tsgs=None, cigars=None, **kwargs):
         if tsgs is not None:
             for prefixer, seqner, ssaider, sigers in tsgs:  # iterate over each tsg
                 if sender != prefixer.qb64:  # sig not by aid
-                    raise MissingSignatureError("Exchange process: skipped signature not from aid="
-                                                "%s on exn msg=\n%s\n", sender, serder.pretty())
+                    raise MissingSignatureError(f"Exchange process: skipped signature not from aid="
+                                                f"{sender}, from {prefixer.qb64} on exn msg=\n{serder.pretty()}\n")
 
                 if prefixer.qb64 not in self.kevers or self.kevers[prefixer.qb64].sn < seqner.sn:
                     if self.escrowPSEvent(serder=serder, tsgs=tsgs, pathed=pathed):

src/keri/vdr/credentialing.py

@@ -980,7 +980,7 @@ def sendArtifacts(hby, reger, postman, creder, recp):
             postman.send(serder=serder, attachment=atc)
 
     for msg in reger.clonePreIter(pre=creder.said):
-        serder = serdering.SerderACDC(raw=msg) # coring.Serder(raw=msg)
+        serder = serdering.SerderKERI(raw=msg) # coring.Serder(raw=msg)
         atc = msg[serder.size:]
         postman.send(serder=serder, attachment=atc)