diff --git a/app/builders/contact_inbox_builder.rb b/app/builders/contact_inbox_builder.rb
index 8fcd2b158..ffa45db2e 100644
--- a/app/builders/contact_inbox_builder.rb
+++ b/app/builders/contact_inbox_builder.rb
@@ -64,5 +64,40 @@ class ContactInboxBuilder
       inbox_id: @inbox.id,
       source_id: @source_id
     )
+  rescue ActiveRecord::RecordNotUnique
+    Rails.logger.info("[ContactInboxBuilder] RecordNotUnique #{@source_id} #{@contact.id} #{@inbox.id}")
+    update_old_contact_inbox
+    retry
+  end
+
+  def update_old_contact_inbox
+    # The race condition occurs when there’s a contact inbox with the
+    # same source ID but linked to a different contact. This can happen
+    # if the agent updates the contact’s email or phone number, or
+    # if the contact is merged with another.
+    #
+    # We update the old contact inbox source_id to a random value to
+    # avoid disrupting the current flow. However, the root cause of
+    # this issue is a flaw in the contact inbox model design.
+    # Contact inbox is essentially tracking a session and is not
+    # needed for non-live chat channels.
+    raise ActiveRecord::RecordNotUnique unless allowed_channels?
+
+    contact_inbox = ::ContactInbox.find_by(inbox_id: @inbox.id, source_id: @source_id)
+    return if contact_inbox.blank?
+
+    contact_inbox.update!(source_id: new_source_id)
+  end
+
+  def new_source_id
+    if @inbox.whatsapp? || @inbox.sms? || @inbox.twilio?
+      "whatsapp:#{@source_id}#{rand(100)}"
+    else
+      "#{rand(10)}#{@source_id}"
+    end
+  end
+
+  def allowed_channels?
+    @inbox.email? || @inbox.sms? || @inbox.twilio? || @inbox.whatsapp?
   end
 end
diff --git a/app/models/inbox.rb b/app/models/inbox.rb
index 2c08172ff..508675858 100644
--- a/app/models/inbox.rb
+++ b/app/models/inbox.rb
@@ -98,6 +98,10 @@ class Inbox < ApplicationRecord
     update_account_cache
   end
 
+  def sms?
+    channel_type == 'Channel::Sms'
+  end
+
   def facebook?
     channel_type == 'Channel::FacebookPage'
   end
diff --git a/spec/builders/contact_inbox_builder_spec.rb b/spec/builders/contact_inbox_builder_spec.rb
index 1dda58063..f0e3deb31 100644
--- a/spec/builders/contact_inbox_builder_spec.rb
+++ b/spec/builders/contact_inbox_builder_spec.rb
@@ -330,5 +330,42 @@ describe ContactInboxBuilder do
         expect(contact_inbox.source_id).not_to be_nil
       end
     end
+
+    context 'when there is a race condition' do
+      let(:account) { create(:account) }
+      let(:contact) { create(:contact, account: account) }
+      let(:contact2) { create(:contact, account: account) }
+      let(:channel) { create(:channel_email, account: account) }
+      let(:channel_api) { create(:channel_api, account: account) }
+      let(:source_id) { 'source_123' }
+
+      it 'handles RecordNotUnique error by updating source_id and retrying' do
+        existing_contact_inbox = create(:contact_inbox, contact: contact2, inbox: channel.inbox, source_id: source_id)
+
+        described_class.new(
+          contact: contact,
+          inbox: channel.inbox,
+          source_id: source_id
+        ).perform
+
+        expect(ContactInbox.last.source_id).to eq(source_id)
+        expect(ContactInbox.last.contact_id).to eq(contact.id)
+        expect(ContactInbox.last.inbox_id).to eq(channel.inbox.id)
+        expect(existing_contact_inbox.reload.source_id).to include(source_id)
+        expect(existing_contact_inbox.reload.source_id).not_to eq(source_id)
+      end
+
+      it 'does not update source_id for channels other than email or phone number' do
+        create(:contact_inbox, contact: contact2, inbox: channel_api.inbox, source_id: source_id)
+
+        expect do
+          described_class.new(
+            contact: contact,
+            inbox: channel_api.inbox,
+            source_id: source_id
+          ).perform
+        end.to raise_error(ActiveRecord::RecordNotUnique)
+      end
+    end
   end
 end