diff --git a/srtcore/group.cpp b/srtcore/group.cpp
index e7f40d884..6b0b16484 100644
--- a/srtcore/group.cpp
+++ b/srtcore/group.cpp
@@ -517,7 +517,11 @@ void CUDTGroup::deriveSettings(CUDT* u)
     IM(SRTO_UDP_RCVBUF, iUDPRcvBufSize);
     // SRTO_RENDEZVOUS: impossible to have it set on a listener socket.
     // SRTO_SNDTIMEO/RCVTIMEO: groupwise setting
-    IM(SRTO_CONNTIMEO, tdConnTimeOut);
+
+    // SRTO_CONNTIMEO requires a special handling, because API stores the value in integer milliseconds,
+    // but the type of the variable is srt::sync::duration.
+    importOption(m_config, SRTO_CONNTIMEO, (int) count_milliseconds(u->m_config.tdConnTimeOut));
+
     IM(SRTO_DRIFTTRACER, bDriftTracer);
     // Reuseaddr: true by default and should only be true.
     IM(SRTO_MAXBW, llMaxBW);
@@ -530,7 +534,9 @@ void CUDTGroup::deriveSettings(CUDT* u)
     IM(SRTO_RCVLATENCY, iRcvLatency);
     IM(SRTO_PEERLATENCY, iPeerLatency);
     IM(SRTO_SNDDROPDELAY, iSndDropDelay);
-    IM(SRTO_PAYLOADSIZE, zExpPayloadSize);
+    // Special handling of SRTO_PAYLOADSIZE becuase API stores the value as int32_t,
+    // while the config structure stores it as size_t.
+    importOption(m_config, SRTO_PAYLOADSIZE, (int)u->m_config.zExpPayloadSize);
     IMF(SRTO_TLPKTDROP, m_bTLPktDrop);
 
     importOption(m_config, SRTO_STREAMID, u->m_config.sStreamName.str());
@@ -544,7 +550,7 @@ void CUDTGroup::deriveSettings(CUDT* u)
 
     importOption(m_config, SRTO_PACKETFILTER, u->m_config.sPacketFilterConfig.str());
 
-    importOption(m_config, SRTO_PBKEYLEN, u->m_pCryptoControl->KeyLen());
+    importOption(m_config, SRTO_PBKEYLEN, (int) u->m_pCryptoControl->KeyLen());
 
     // Passphrase is empty by default. Decipher the passphrase and
     // store as passphrase option
@@ -824,7 +830,7 @@ void CUDTGroup::getOpt(SRT_SOCKOPT optname, void* pw_optval, int& w_optlen)
     if (w_optlen < int(i->value.size()))
         throw CUDTException(MJ_NOTSUP, MN_XSIZE, 0);
 
-    w_optlen = i->value.size();
+    w_optlen = (int) i->value.size();
     memcpy((pw_optval), &i->value[0], i->value.size());
 }