diff --git a/imapserver/server.go b/imapserver/server.go
index 2d29abe..5c4971f 100644
--- a/imapserver/server.go
+++ b/imapserver/server.go
@@ -288,8 +288,8 @@ var commands = map[string]func(c *conn, tag, cmd string, p *parser){
 	"uid move":    (*conn).cmdUIDMove,
 }
 
-var errIO = errors.New("fatal io error")             // For read/write errors and errors that should close the connection.
-var errProtocol = errors.New("fatal protocol error") // For protocol errors for which a stack trace should be printed.
+var errIO = errors.New("io error")             // For read/write errors and errors that should close the connection.
+var errProtocol = errors.New("protocol error") // For protocol errors for which a stack trace should be printed.
 
 var sanityChecks bool
 
diff --git a/smtpserver/server.go b/smtpserver/server.go
index af9d9e4..4bee75d 100644
--- a/smtpserver/server.go
+++ b/smtpserver/server.go
@@ -63,7 +63,7 @@ var xlog = mlog.New("smtpserver")
 
 // We use panic and recover for error handling while executing commands.
 // These errors signal the connection must be closed.
-var errIO = errors.New("fatal io error")
+var errIO = errors.New("io error")
 
 // If set, regular delivery/submit is sidestepped, email is accepted and
 // delivered to the account named mox.