diff --git a/src/common/p25/lc/tsbk/ISP_AUTH_RESP.cpp b/src/common/p25/lc/tsbk/ISP_AUTH_RESP.cpp
index 66ffa24c..605c1300 100644
--- a/src/common/p25/lc/tsbk/ISP_AUTH_RESP.cpp
+++ b/src/common/p25/lc/tsbk/ISP_AUTH_RESP.cpp
@@ -67,10 +67,10 @@ bool ISP_AUTH_RESP::decode(const uint8_t* data, bool rawTSBK)
     ulong64_t tsbkValue = TSBK::toValue(tsbk);
 
     m_authStandalone = (((tsbkValue >> 56) & 0xFFU) & 0x01U) == 0x01U;              // Authentication Standalone Flag
-    m_authRes[0U] = tsbk[3U];                                                       // RES1(3)
-    m_authRes[1U] = tsbk[4U];                                                       // RES1(2)
-    m_authRes[2U] = tsbk[5U];                                                       // RES1(1)
-    m_authRes[3U] = tsbk[6U];                                                       // RES1(0)
+    m_authRes[0U] = tsbk[1U];                                                       // RES1(3)
+    m_authRes[1U] = tsbk[2U];                                                       // RES1(2)
+    m_authRes[2U] = tsbk[3U];                                                       // RES1(1)
+    m_authRes[3U] = tsbk[4U];                                                       // RES1(0)
 
     m_srcId = (uint32_t)(tsbkValue & 0xFFFFFFU);                                    // Source Radio Address