diff --git a/lib/curl_sasl.c b/lib/curl_sasl.c
index 94b51e541..c609b1ded 100644
--- a/lib/curl_sasl.c
+++ b/lib/curl_sasl.c
@@ -367,7 +367,7 @@ CURLcode Curl_sasl_start(struct SASL *sasl, struct connectdata *conn,
       sasl->authused = SASL_MECH_PLAIN;
 
       if(force_ir || data->set.sasl_ir)
-        result = Curl_auth_create_plain_message(data, conn->user, conn->user,
+        result = Curl_auth_create_plain_message(data, NULL, conn->user,
                                                 conn->passwd, &resp, &len);
     }
     else if(enabledmechs & SASL_MECH_LOGIN) {
@@ -450,7 +450,7 @@ CURLcode Curl_sasl_continue(struct SASL *sasl, struct connectdata *conn,
     *progress = SASL_DONE;
     return result;
   case SASL_PLAIN:
-    result = Curl_auth_create_plain_message(data, conn->user, conn->user,
+    result = Curl_auth_create_plain_message(data, NULL, conn->user,
                                             conn->passwd, &resp, &len);
     break;
   case SASL_LOGIN:
diff --git a/tests/data/test819 b/tests/data/test819
index b88e35055..4213e3ea6 100644
--- a/tests/data/test819
+++ b/tests/data/test819
@@ -14,7 +14,7 @@ RFC4616
 <servercmd>
 AUTH PLAIN
 REPLY AUTHENTICATE +
-REPLY dXNlcgB1c2VyAHNlY3JldA== A002 OK AUTHENTICATE completed
+REPLY AHVzZXIAc2VjcmV0 A002 OK AUTHENTICATE completed
 </servercmd>
 <data>
 From: me@somewhere
@@ -47,7 +47,7 @@ IMAP plain authentication
 <protocol>
 A001 CAPABILITY
 A002 AUTHENTICATE PLAIN
-dXNlcgB1c2VyAHNlY3JldA==
+AHVzZXIAc2VjcmV0
 A003 SELECT 819
 A004 FETCH 1 BODY[]
 A005 LOGOUT
diff --git a/tests/data/test825 b/tests/data/test825
index b489e95de..d28b6a519 100644
--- a/tests/data/test825
+++ b/tests/data/test825
@@ -47,7 +47,7 @@ IMAP plain authentication with initial response
 <verify>
 <protocol>
 A001 CAPABILITY
-A002 AUTHENTICATE PLAIN dXNlcgB1c2VyAHNlY3JldA==
+A002 AUTHENTICATE PLAIN AHVzZXIAc2VjcmV0
 A003 SELECT 825
 A004 FETCH 1 BODY[]
 A005 LOGOUT
diff --git a/tests/data/test833 b/tests/data/test833
index dc8214b8e..2c694adcc 100644
--- a/tests/data/test833
+++ b/tests/data/test833
@@ -18,7 +18,7 @@ AUTH CRAM-MD5 PLAIN
 REPLY "AUTHENTICATE CRAM-MD5" + Rubbish
 REPLY * A002 NO AUTH exchange cancelled by client
 REPLY "AUTHENTICATE PLAIN" +
-REPLY dXNlcgB1c2VyAHNlY3JldA== A003 OK AUTHENTICATE completed
+REPLY AHVzZXIAc2VjcmV0 A003 OK AUTHENTICATE completed
 </servercmd>
 <data>
 From: me@somewhere
@@ -56,7 +56,7 @@ A001 CAPABILITY
 A002 AUTHENTICATE CRAM-MD5
 *
 A003 AUTHENTICATE PLAIN
-dXNlcgB1c2VyAHNlY3JldA==
+AHVzZXIAc2VjcmV0
 A004 SELECT 833
 A005 FETCH 1 BODY[]
 A006 LOGOUT
diff --git a/tests/data/test834 b/tests/data/test834
index fc131773b..35ab06aff 100644
--- a/tests/data/test834
+++ b/tests/data/test834
@@ -18,7 +18,7 @@ REPLY "AUTHENTICATE NTLM" +
 REPLY TlRMTVNTUAABAAAABoIIAAAAAAAAAAAAAAAAAAAAAAA= + Rubbish
 REPLY * A002 NO AUTH exchange cancelled by client
 REPLY "AUTHENTICATE PLAIN" +
-REPLY dXNlcgB1c2VyAHNlY3JldA== A003 OK AUTHENTICATE completed
+REPLY AHVzZXIAc2VjcmV0 A003 OK AUTHENTICATE completed
 </servercmd>
 <data>
 From: me@somewhere
@@ -67,7 +67,7 @@ A002 AUTHENTICATE NTLM
 TlRMTVNTUAABAAAABoIIAAAAAAAAAAAAAAAAAAAAAAA=
 *
 A003 AUTHENTICATE PLAIN
-dXNlcgB1c2VyAHNlY3JldA==
+AHVzZXIAc2VjcmV0
 A004 SELECT 834
 A005 FETCH 1 BODY[]
 A006 LOGOUT
diff --git a/tests/data/test835 b/tests/data/test835
index 400233c0c..b44e877ec 100644
--- a/tests/data/test835
+++ b/tests/data/test835
@@ -18,7 +18,7 @@ AUTH DIGEST-MD5 PLAIN
 REPLY "AUTHENTICATE DIGEST-MD5" + Rubbish
 REPLY * A002 NO AUTH exchange cancelled by client
 REPLY "AUTHENTICATE PLAIN" +
-REPLY dXNlcgB1c2VyAHNlY3JldA== A003 OK AUTHENTICATE completed
+REPLY AHVzZXIAc2VjcmV0 A003 OK AUTHENTICATE completed
 </servercmd>
 <data>
 From: me@somewhere
@@ -58,7 +58,7 @@ A001 CAPABILITY
 A002 AUTHENTICATE DIGEST-MD5
 *
 A003 AUTHENTICATE PLAIN
-dXNlcgB1c2VyAHNlY3JldA==
+AHVzZXIAc2VjcmV0
 A004 SELECT 835
 A005 FETCH 1 BODY[]
 A006 LOGOUT
diff --git a/tests/data/test865 b/tests/data/test865
index 6f66f82d7..8a262fcc5 100644
--- a/tests/data/test865
+++ b/tests/data/test865
@@ -16,7 +16,7 @@ RFC5034
 <servercmd>
 AUTH PLAIN
 REPLY AUTH +
-REPLY dXNlcgB1c2VyAHNlY3JldA== +OK Login successful
+REPLY AHVzZXIAc2VjcmV0 +OK Login successful
 </servercmd>
 <data>
 From: me@somewhere
@@ -49,7 +49,7 @@ pop3://%HOSTIP:%POP3PORT/865 -u user:secret
 <protocol>
 CAPA
 AUTH PLAIN
-dXNlcgB1c2VyAHNlY3JldA==
+AHVzZXIAc2VjcmV0
 RETR 865
 QUIT
 </protocol>
diff --git a/tests/data/test871 b/tests/data/test871
index f4f236041..27cc2a4b3 100644
--- a/tests/data/test871
+++ b/tests/data/test871
@@ -48,7 +48,7 @@ pop3://%HOSTIP:%POP3PORT/871 -u user:secret --sasl-ir
 <verify>
 <protocol>
 CAPA
-AUTH PLAIN dXNlcgB1c2VyAHNlY3JldA==
+AUTH PLAIN AHVzZXIAc2VjcmV0
 RETR 871
 QUIT
 </protocol>
diff --git a/tests/data/test879 b/tests/data/test879
index 681d779b2..0d45aaa20 100644
--- a/tests/data/test879
+++ b/tests/data/test879
@@ -20,7 +20,7 @@ AUTH CRAM-MD5 PLAIN
 REPLY "AUTH CRAM-MD5" + Rubbish
 REPLY * -ERR AUTH exchange cancelled by client
 REPLY "AUTH PLAIN" +
-REPLY dXNlcgB1c2VyAHNlY3JldA== +OK Login successful
+REPLY AHVzZXIAc2VjcmV0 +OK Login successful
 </servercmd>
 <data>
 From: me@somewhere
@@ -58,7 +58,7 @@ CAPA
 AUTH CRAM-MD5
 *
 AUTH PLAIN
-dXNlcgB1c2VyAHNlY3JldA==
+AHVzZXIAc2VjcmV0
 RETR 879
 QUIT
 </protocol>
diff --git a/tests/data/test880 b/tests/data/test880
index f5eb69731..738817cd3 100644
--- a/tests/data/test880
+++ b/tests/data/test880
@@ -20,7 +20,7 @@ REPLY "AUTH NTLM" +
 REPLY TlRMTVNTUAABAAAABoIIAAAAAAAAAAAAAAAAAAAAAAA= + Rubbish
 REPLY * -ERR AUTH exchange cancelled by client
 REPLY "AUTH PLAIN" +
-REPLY dXNlcgB1c2VyAHNlY3JldA== +OK Login successful
+REPLY AHVzZXIAc2VjcmV0 +OK Login successful
 </servercmd>
 <data>
 From: me@somewhere
@@ -69,7 +69,7 @@ AUTH NTLM
 TlRMTVNTUAABAAAABoIIAAAAAAAAAAAAAAAAAAAAAAA=
 *
 AUTH PLAIN
-dXNlcgB1c2VyAHNlY3JldA==
+AHVzZXIAc2VjcmV0
 RETR 880
 QUIT
 </protocol>
diff --git a/tests/data/test881 b/tests/data/test881
index 80eca500c..ccb906d9d 100644
--- a/tests/data/test881
+++ b/tests/data/test881
@@ -20,7 +20,7 @@ AUTH DIGEST-MD5 PLAIN
 REPLY "AUTH DIGEST-MD5" + Rubbish
 REPLY * -ERR AUTH exchange cancelled by client
 REPLY "AUTH PLAIN" +
-REPLY dXNlcgB1c2VyAHNlY3JldA== +OK Login successful
+REPLY AHVzZXIAc2VjcmV0 +OK Login successful
 </servercmd>
 <data>
 From: me@somewhere
@@ -60,7 +60,7 @@ CAPA
 AUTH DIGEST-MD5
 *
 AUTH PLAIN
-dXNlcgB1c2VyAHNlY3JldA==
+AHVzZXIAc2VjcmV0
 RETR 881
 QUIT
 </protocol>
diff --git a/tests/data/test903 b/tests/data/test903
index 2baf5e696..8a766e56d 100644
--- a/tests/data/test903
+++ b/tests/data/test903
@@ -15,7 +15,7 @@ RFC4954
 <servercmd>
 AUTH PLAIN
 REPLY AUTH 334 PLAIN supported
-REPLY dXNlcgB1c2VyAHNlY3JldA== 235 Authenticated
+REPLY AHVzZXIAc2VjcmV0 235 Authenticated
 </servercmd>
 </reply>
 
@@ -42,7 +42,7 @@ smtp://%HOSTIP:%SMTPPORT/903 --mail-rcpt recipient@example.com --mail-from sende
 <protocol>
 EHLO 903
 AUTH PLAIN
-dXNlcgB1c2VyAHNlY3JldA==
+AHVzZXIAc2VjcmV0
 MAIL FROM:<sender@example.com>
 RCPT TO:<recipient@example.com>
 DATA
diff --git a/tests/data/test919 b/tests/data/test919
index 3e74494cb..39794e30b 100644
--- a/tests/data/test919
+++ b/tests/data/test919
@@ -41,7 +41,7 @@ smtp://%HOSTIP:%SMTPPORT/919 --mail-rcpt recipient@example.com --mail-from sende
 <verify>
 <protocol>
 EHLO 919
-AUTH PLAIN dXNlcgB1c2VyAHNlY3JldA==
+AUTH PLAIN AHVzZXIAc2VjcmV0
 MAIL FROM:<sender@example.com>
 RCPT TO:<recipient@example.com>
 DATA
diff --git a/tests/data/test935 b/tests/data/test935
index 3fd5c2e50..946611477 100644
--- a/tests/data/test935
+++ b/tests/data/test935
@@ -19,7 +19,7 @@ AUTH CRAM-MD5 PLAIN
 REPLY "AUTH CRAM-MD5" 334 Rubbish
 REPLY * 501 AUTH exchange cancelled by client
 REPLY "AUTH PLAIN" 334 PLAIN supported
-REPLY dXNlcgB1c2VyAHNlY3JldA== 235 Authenticated
+REPLY AHVzZXIAc2VjcmV0 235 Authenticated
 </servercmd>
 </reply>
 
@@ -51,7 +51,7 @@ EHLO 935
 AUTH CRAM-MD5
 *
 AUTH PLAIN
-dXNlcgB1c2VyAHNlY3JldA==
+AHVzZXIAc2VjcmV0
 MAIL FROM:<sender@example.com>
 RCPT TO:<recipient@example.com>
 DATA
diff --git a/tests/data/test936 b/tests/data/test936
index 88c8a937e..5fde3c967 100644
--- a/tests/data/test936
+++ b/tests/data/test936
@@ -19,7 +19,7 @@ REPLY "AUTH NTLM" 334 NTLM supported
 REPLY TlRMTVNTUAABAAAABoIIAAAAAAAAAAAAAAAAAAAAAAA= 334 Rubbish
 REPLY * 501 AUTH exchange cancelled by client
 REPLY "AUTH PLAIN" 334 PLAIN supported
-REPLY dXNlcgB1c2VyAHNlY3JldA== 235 Authenticated
+REPLY AHVzZXIAc2VjcmV0 235 Authenticated
 </servercmd>
 </reply>
 
@@ -62,7 +62,7 @@ AUTH NTLM
 TlRMTVNTUAABAAAABoIIAAAAAAAAAAAAAAAAAAAAAAA=
 *
 AUTH PLAIN
-dXNlcgB1c2VyAHNlY3JldA==
+AHVzZXIAc2VjcmV0
 MAIL FROM:<sender@example.com>
 RCPT TO:<recipient@example.com>
 DATA
diff --git a/tests/data/test937 b/tests/data/test937
index a2cb9b5c0..5e729e308 100644
--- a/tests/data/test937
+++ b/tests/data/test937
@@ -19,7 +19,7 @@ AUTH DIGEST-MD5 PLAIN
 REPLY "AUTH DIGEST-MD5" 334 Rubbish
 REPLY * 501 AUTH exchange cancelled by client
 REPLY "AUTH PLAIN" 334 PLAIN supported
-REPLY dXNlcgB1c2VyAHNlY3JldA== 235 Authenticated
+REPLY AHVzZXIAc2VjcmV0 235 Authenticated
 </servercmd>
 </reply>
 
@@ -53,7 +53,7 @@ EHLO 937
 AUTH DIGEST-MD5
 *
 AUTH PLAIN
-dXNlcgB1c2VyAHNlY3JldA==
+AHVzZXIAc2VjcmV0
 MAIL FROM:<sender@example.com>
 RCPT TO:<recipient@example.com>
 DATA