Chroma "Could not connect to tenant default_tenant" Error

How to fix it

Try these in order — the most common fix is first.

1. 1. Start and check the server

   Copy steps
   1. pip install "chromadb[server]"
   2. chroma run --host 0.0.0.0 --port 8000 --path ./chroma_data
   3. In code: chromadb.HttpClient(host, port) then client.heartbeat()
   Did this fix it? Yes No

2. 2. Match versions

   1. Pin client and server to the same Chroma version
   Did this fix it? Yes No

Symptoms

ConnectionError: Could not connect to tenant default_tenant at http://localhost:8000.

Why it happens

• Server not running
• Wrong host or port in Docker
• Client and server on different versions

This guide also covers

• chromadb could not connect to tenant default_tenant
• chroma server not running
• chromadb httpclient connection error

The same problem in other apps

All not loading, error messages & connection guides →

• Qdrant "Wrong input: Vector dimension error: expected dim, got" (Qdrant)
• Pinecone 429 Too Many Requests Error (Pinecone)
• Milvus "collection not loaded" Error (Milvus)
• Weaviate Error: Vector Lengths Don't Match (Weaviate)

Other Chroma errors

• Chroma "Your system has an unsupported version of sqlite3" Error
• Chroma InvalidDimensionException: Embedding Dimension Does Not Match Collection
• Chroma pip install "Failed to build hnswlib" Error
• Chroma Data Disappears After Restart (Persistence Fix)
• Chroma "Collection Not Found" Error
• Chroma "Collection Already Exists" UniqueConstraintError
• Chroma "sqlite3.OperationalError: database is locked"
• Chroma "Cannot return the results in a contiguous 2D array. Probably ef or M is too small"