diff --git a/zetaclient/zetacore_observer.go b/zetaclient/zetacore_observer.go
index b6e48b0264..d482e8cc32 100644
--- a/zetaclient/zetacore_observer.go
+++ b/zetaclient/zetacore_observer.go
@@ -3,7 +3,6 @@ package zetaclient
 import (
 	"fmt"
 	"math"
-	"sort"
 	"strings"
 	"time"
 
@@ -123,7 +122,10 @@ func (co *CoreObserver) startSendScheduler() {
 
 					supportedChains := GetSupportedChains()
 					for _, c := range supportedChains {
-
+						if c == nil {
+							co.logger.ZetaChainWatcher.Error().Msg("chain nil")
+							continue
+						}
 						signer := co.signerMap[*c]
 						chainClient := co.clientMap[*c]
 						sendList, err := co.bridge.GetAllPendingCctx(uint64(c.ChainId))
@@ -131,6 +133,14 @@ func (co *CoreObserver) startSendScheduler() {
 							co.logger.ZetaChainWatcher.Error().Err(err).Msgf("failed to GetAllPendingCctx for chain %s", c.ChainName.String())
 							continue
 						}
+						res, err := co.bridge.GetAllOutTxTrackerByChain(*c)
+						if err != nil {
+							co.logger.ZetaChainWatcher.Warn().Err(err).Msgf("failed to GetAllOutTxTrackerByChain for chain %s", c.ChainName.String())
+						}
+						trackerMap := make(map[uint64]bool)
+						for _, v := range res {
+							trackerMap[v.Nonce] = true
+						}
 
 						for idx, send := range sendList {
 							if send.GetCurrentOutTxParam().ReceiverChainId != c.ChainId {
@@ -180,7 +190,27 @@ func (co *CoreObserver) startSendScheduler() {
 								co.logger.ZetaChainWatcher.Error().Msgf("unknown ob type on chain %s: type %T", chain, ob)
 								continue
 							}
-							if nonce%interval == currentHeight%interval && !outTxMan.IsOutTxActive(outTxID) {
+
+							// determining critical outtx; if it satisfies following criteria
+							// 1. it's the first pending outtx for this chain
+							// 2. the following 5 nonces have been in tracker
+							isCritical := false
+							criticalInterval := uint64(10) // for critical pending outTx we reduce re-try interval
+							if nonce%criticalInterval == currentHeight%criticalInterval && idx == 0 {
+								nextFiveNonce := true
+								for i := nonce + 1; i <= nonce+5; i++ {
+									if _, found := trackerMap[i]; !found {
+										nextFiveNonce = false
+										break
+									}
+								}
+								if nextFiveNonce {
+									isCritical = true
+									break
+								}
+							}
+
+							if (isCritical || nonce%interval == currentHeight%interval) && !outTxMan.IsOutTxActive(outTxID) {
 								outTxMan.StartTryProcess(outTxID)
 								co.logger.ZetaChainWatcher.Debug().Msgf("chain %s: Sign outtx %s with value %d\n", chain, send.Index, send.GetCurrentOutTxParam().Amount)
 								go signer.TryProcessOutTx(send, outTxMan, outTxID, chainClient, co.bridge, currentHeight)
@@ -200,44 +230,6 @@ func (co *CoreObserver) startSendScheduler() {
 	}
 }
 
-// trim "bogus" pending sends that are not actually pending
-// input sends must be sorted by nonce ascending
-func trimSends(sends []*types.CrossChainTx) int {
-	start := 0
-	for i := len(sends) - 1; i >= 1; i-- {
-		// from right to left, if there's a big hole, then before the gap are probably
-		// bogus "pending" sends that are already processed but not yet confirmed.
-		if sends[i].GetCurrentOutTxParam().OutboundTxTssNonce > sends[i-1].GetCurrentOutTxParam().OutboundTxTssNonce+1000 {
-			start = i
-			break
-		}
-	}
-	return start
-}
-
-func SplitAndSortSendListByChain(sendList []*types.CrossChainTx) map[string][]*types.CrossChainTx {
-	sendMap := make(map[string][]*types.CrossChainTx)
-	for _, send := range sendList {
-		targetChain, err := GetTargetChain(send)
-		if targetChain == "" || err != nil {
-			continue
-		}
-		if _, found := sendMap[targetChain]; !found {
-			sendMap[targetChain] = make([]*types.CrossChainTx, 0)
-		}
-		sendMap[targetChain] = append(sendMap[targetChain], send)
-	}
-	for chain, sends := range sendMap {
-		sort.Slice(sends, func(i, j int) bool {
-			return sends[i].GetCurrentOutTxParam().OutboundTxTssNonce < sends[j].GetCurrentOutTxParam().OutboundTxTssNonce
-		})
-		start := trimSends(sends)
-		sendMap[chain] = sends[start:]
-		log.Debug().Msgf("chain %s, start %d, len %d, start nonce %d", chain, start, len(sendMap[chain]), sends[start].GetCurrentOutTxParam().OutboundTxTssNonce)
-	}
-	return sendMap
-}
-
 func GetTargetChain(send *types.CrossChainTx) (string, error) {
 	chainID := send.GetCurrentOutTxParam().ReceiverChainId
 	chain := common.GetChainFromChainID(chainID)