diff --git a/packages/core/src/network/authorization.ts b/packages/core/src/network/authorization.ts
index a9d5d7fd..b8e83224 100644
--- a/packages/core/src/network/authorization.ts
+++ b/packages/core/src/network/authorization.ts
@@ -333,6 +333,7 @@ export async function doAuthorization(
 
     const dhPrime = bufferToBigInt(serverDhInner.dhPrime)
     const timeOffset = Math.floor(Date.now() / 1000) - serverDhInner.serverTime
+    session.updateTimeOffset(timeOffset)
 
     const g = BigInt(serverDhInner.g)
     const gA = bufferToBigInt(serverDhInner.gA)
diff --git a/packages/core/src/network/mtproto-session.ts b/packages/core/src/network/mtproto-session.ts
index 9d4342bf..9f9b0be8 100644
--- a/packages/core/src/network/mtproto-session.ts
+++ b/packages/core/src/network/mtproto-session.ts
@@ -169,6 +169,13 @@ export class MtprotoSession {
         this._authKeyTempSecondary.reset()
     }
 
+    updateTimeOffset(offset: number) {
+        this._timeOffset = offset
+        // lastMessageId was generated with (potentially) wrong time
+        // reset it to avoid bigger issues - at worst, we'll get bad_msg_notification
+        this._lastMessageId = Long.ZERO
+    }
+
     /**
      * Reset session state and generate a new session ID.
      *
@@ -230,7 +237,7 @@ export class MtprotoSession {
 
     getMessageId(): Long {
         const timeTicks = Date.now()
-        const timeSec = Math.floor(timeTicks / 1000) + this._timeOffset
+        const timeSec = Math.floor(timeTicks / 1000) - this._timeOffset
         const timeMSec = timeTicks % 1000
         const random = getRandomInt(0xffff)
 
diff --git a/packages/core/src/network/session-connection.ts b/packages/core/src/network/session-connection.ts
index 753a68de..cda4381f 100644
--- a/packages/core/src/network/session-connection.ts
+++ b/packages/core/src/network/session-connection.ts
@@ -281,7 +281,7 @@ export class SessionConnection extends PersistentConnection {
             .then(([authKey, serverSalt, timeOffset]) => {
                 this._session._authKey.setup(authKey)
                 this._salts.currentSalt = serverSalt
-                this._session._timeOffset = timeOffset
+                this._session.updateTimeOffset(timeOffset)
 
                 this._session.authorizationPending = false
 
@@ -1092,10 +1092,10 @@ export class SessionConnection extends PersistentConnection {
                     // msg_id is either too high or too low
                     // code 20 means msg_id is too old,
                     // we just need to resend the message
-                    const serverTime = msgId.low >>> 0
+                    const serverTime = msgId.high >>> 0
                     const timeOffset = Math.floor(Date.now() / 1000) - serverTime
 
-                    this._session._timeOffset = timeOffset
+                    this._session.updateTimeOffset(timeOffset)
                     this.log.debug('server time: %d, corrected offset to %d', serverTime, timeOffset)
                 }