diff --git a/src/impl/chain/contract.ts b/src/impl/chain/contract.ts
index 92f3b83..a0e6fa3 100644
--- a/src/impl/chain/contract.ts
+++ b/src/impl/chain/contract.ts
@@ -70,11 +70,16 @@ export class ContractHelper {
   async connect(url: string): Promise<provider> {
     const provider = new Web3.providers.WebsocketProvider(url, {
       reconnect: {
-        auto: true,
+        auto: false,
         delay: 5000,
         maxAttempts: 5,
-        onTimeout: false,
+        onTimeout: true,
       },
+      clientConfig: {
+        keepalive: true,
+        keepaliveInterval: 60000, // ms
+      },
+      timeout: 30000,
     });
     return new Promise((resolve, reject) => {
       provider.on("connect", () => {
@@ -122,22 +127,44 @@ export class ContractHelper {
     });
     const serializedTx = "0x" + tx.sign(key).serialize().toString("hex");
     return new Promise((resolve, reject) => {
-      this.web3.eth
-        .sendSignedTransaction(serializedTx)
-        .then((receipt) => {
-          if (receipt.status) {
-            resolve(receipt);
-          } else {
-            const err = `method ${name} tx hash ${receipt.transactionHash} is reverted`;
-            reject(err);
-          }
-        })
-        .catch((err: Error) => {
+      this.web3.eth.sendSignedTransaction(serializedTx, (err: Error, hash: string) => {
+        if (err) {
           reject(err);
-        });
+        } else {
+          resolve(this.waitForReceipt(hash));
+        }
+      });
     });
   }
 
+  async waitForReceipt(hash: string, retry: number = 3): Promise<TransactionReceipt> {
+    if (retry === 0) {
+      throw new Error(`unable to get transaction receipt for tx ${hash}`);
+    }
+    try {
+      const receipt = await this.web3.eth.getTransactionReceipt(hash);
+      if (receipt) {
+        if (receipt.status == true) {
+          return receipt;
+        } else {
+          throw new Error(`tx ${receipt.transactionHash} is reverted`);
+        }
+      } else {
+        return await this.waitForReceipt(hash);
+      }
+    } catch (err) {
+      if (
+        err instanceof Error &&
+        err.message.includes("CONNECTION ERROR") &&
+        err.message.includes("reconnect")
+      ) {
+        return await this.waitForReceipt(hash, retry - 1);
+      } else {
+        throw err;
+      }
+    }
+  }
+
   decodeLogs(logs: Log[]): Result | undefined {
     for (const rlog of logs) {
       const topics = rlog.topics;
diff --git a/src/service/server.ts b/src/service/server.ts
index b730bc8..55b3c86 100644
--- a/src/service/server.ts
+++ b/src/service/server.ts
@@ -11,7 +11,12 @@ export function run(host: string, port: number): void {
     oneofs: true,
   });
   const proto = grpc.loadPackageDefinition(definition) as unknown as ProtoGrpcType;
-  const server = new grpc.Server();
+  const server = new grpc.Server({
+    "grpc.keepalive_time_ms": 10000,
+    "grpc.keepalive_timeout_ms": 5000,
+    "grpc.keepalive_permit_without_calls": 1,
+    "grpc.max_pings_without_data": 0,
+  });
   server.addService(proto.chain.Chain.service, chainService);
   server.bindAsync(`${host}:${port}`, grpc.ServerCredentials.createInsecure(), (err, p) => {
     if (err) {