Diagnose and troubleshoot Azure Cosmos DB not found exceptions


The HTTP status code 404 represents that the resource no longer exists.

Expected behavior

There are many valid scenarios where an application expects a code 404 and correctly handles the scenario.

A not found exception was returned for an item that should exist or does exist

Here are the possible reasons for a status code 404 to be returned if the item should exist or does exist.

The read session is not available for the input session token


  1. Update your current SDK to the latest version available. The most common causes for this particular error have been fixed in the newest SDK versions.

Race condition

There are multiple SDK client instances and the read happened before the write.


  1. The default account consistency for Azure Cosmos DB is session consistency. When an item is created or updated, the response returns a session token that can be passed between SDK instances to guarantee that the read request is reading from a replica with that change.
  2. Change the consistency level to a stronger level.

Reading throughput for a container or database resource

Using PowerShell or Azure CLI and receive not found error message.


Throughput can be provisioned at the database level, container level, or both. If getting a not found error, try reading throughput the parent database resource, or child container resource.

Invalid partition key and ID combination

The partition key and ID combination aren't valid.


Fix the application logic that's causing the incorrect combination.

Invalid character in an item ID

An item is inserted into Azure Cosmos DB with an invalid character in the item ID.


Change the ID to a different value that doesn't contain the special characters. If changing the ID isn't an option, you can Base64 encode the ID to escape the special characters. Base64 can still produce a name with a invalid character '/' which needs to be replaced.

Items already inserted in the container for the ID can be replaced by using RID values instead of name-based references.

// Get a container reference that uses RID values.
ContainerProperties containerProperties = await this.Container.ReadContainerAsync();
string[] selfLinkSegments = containerProperties.SelfLink.Split('/');
string databaseRid = selfLinkSegments[1];
string containerRid = selfLinkSegments[3];
Container containerByRid = this.cosmosClient.GetContainer(databaseRid, containerRid);

// Invalid characters are listed here.
// https://learn.microsoft.com/dotnet/api/microsoft.azure.documents.resource.id#remarks
FeedIterator<JObject> invalidItemsIterator = this.Container.GetItemQueryIterator<JObject>(
    @"select * from t where CONTAINS(t.id, ""/"") or CONTAINS(t.id, ""#"") or CONTAINS(t.id, ""?"") or CONTAINS(t.id, ""\\"") ");
while (invalidItemsIterator.HasMoreResults)
    foreach (JObject itemWithInvalidId in await invalidItemsIterator.ReadNextAsync())
        // Choose a new ID that doesn't contain special characters.
        // If that isn't possible, then Base64 encode the ID to escape the special characters.
        byte[] plainTextBytes = Encoding.UTF8.GetBytes(itemWithInvalidId["id"].ToString());
        itemWithInvalidId["id"] = Convert.ToBase64String(plainTextBytes).Replace('/', '!');

        // Update the item with the new ID value by using the RID-based container reference.
        JObject item = await containerByRid.ReplaceItemAsync<JObject>(
            item: itemWithInvalidId,
            ID: itemWithInvalidId["_rid"].ToString(),
            partitionKey: new Cosmos.PartitionKey(itemWithInvalidId["status"].ToString()));

        // Validating the new ID can be read by using the original name-based container reference.
        await this.Container.ReadItemAsync<ToDoActivity>(
            new Cosmos.PartitionKey(item["status"].ToString())); ;

Time to Live purge

The item had the Time to Live (TTL) property set. The item was purged because the TTL property expired.


Change the TTL property to prevent the item from being purged.

Lazy indexing

The lazy indexing hasn't caught up.


Wait for the indexing to catch up or change the indexing policy.

Parent resource deleted

The database or container that the item exists in was deleted.


  1. Restore from a backup the parent resource, or re-create the resources.
  2. Create a new resource to replace the deleted resource.

7. Container/Collection names are case-sensitive

Container/Collection names are case-sensitive in Azure Cosmos DB.


Make sure to use the exact name while connecting to Azure Cosmos DB.

Next steps