diff --git a/CHANGELOG.md b/CHANGELOG.md
index 16348546..6b67f826 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -7,6 +7,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## Unreleased
 
+### Fixed
+
+- Fix Slack access token length issue by @toolchainX ([#3016](https://github.com/grafana/oncall/pull/3016))
+
 ## v1.3.37 (2023-09-12)
 
 ### Added
diff --git a/engine/apps/slack/migrations/0004_auto_20230913_1020.py b/engine/apps/slack/migrations/0004_auto_20230913_1020.py
new file mode 100644
index 00000000..9e58ced1
--- /dev/null
+++ b/engine/apps/slack/migrations/0004_auto_20230913_1020.py
@@ -0,0 +1,23 @@
+# Generated by Django 3.2.20 on 2023-09-13 10:20
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('slack', '0003_delete_slackactionrecord'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='slackteamidentity',
+            name='access_token',
+            field=models.CharField(default=None, max_length=255, null=True),
+        ),
+        migrations.AlterField(
+            model_name='slackteamidentity',
+            name='bot_access_token',
+            field=models.CharField(default=None, max_length=255, null=True),
+        ),
+    ]
diff --git a/engine/apps/slack/models/slack_team_identity.py b/engine/apps/slack/models/slack_team_identity.py
index 60d8b19a..6fe09320 100644
--- a/engine/apps/slack/models/slack_team_identity.py
+++ b/engine/apps/slack/models/slack_team_identity.py
@@ -31,9 +31,9 @@ class SlackTeamIdentity(models.Model):
     slack_id = models.CharField(max_length=100)
     cached_name = models.CharField(max_length=100, null=True, default=None)
     cached_app_id = models.CharField(max_length=100, null=True, default=None)
-    access_token = models.CharField(max_length=100, null=True, default=None)
+    access_token = models.CharField(max_length=255, null=True, default=None)
     bot_user_id = models.CharField(max_length=100, null=True, default=None)
-    bot_access_token = models.CharField(max_length=100, null=True, default=None)
+    bot_access_token = models.CharField(max_length=255, null=True, default=None)
     oauth_scope = models.TextField(max_length=30000, null=True, default=None)
     detected_token_revoked = models.DateTimeField(null=True, default=None, verbose_name="Deleted At")
     is_profile_populated = models.BooleanField(default=False)