Unable to Connect to Azure Managed Redis – Frequent Disconnections from VM

Redis connection from our Azure Virtual Machine to Azure Managed Redis is frequently failing. The VM is unable to maintain a stable connection—either timing out or getting disconnected shortly after connecting. All credentials and configurations appear to be correct.

Steps to Reproduce:

Connect to Azure VM (Linux/Windows).

Use redis-cli or application to connect to Azure Managed Redis:

Host: <your-redis-name>.redis.cache.windows.net

  Port: 6380 (TLS)
  
     Password: (Access key from Azure portal)
     
     Run any Redis command or keep the connection idle.
     

Expected Result: A stable and persistent connection to the Redis instance, allowing commands to be executed normally.

Actual Result: Connection either:

Fails immediately with error:

(error) WRONGPASS invalid username-password pair

  `Could not connect to Redis at <host>:6379: Connection refused`
  
  Or disconnects after a short time
  

Environment Details:

Azure VM OS: [e.g., Ubuntu 20.04 / Windows Server 2022]

Redis Client: redis-cli / StackExchange.Redis / custom app

Redis Hostname: <your-redis-host>.redis.cache.windows.net

Port: 6380

TLS: Enabled

Network Security Group: Port 6380 outbound allowed

DNS Resolution: Working from VM

Troubleshooting Done:

Verified Redis credentials from Azure portal

Ensured VM outbound rules allow port 6380

Tested with and without TLS

Attempted from different VMs

Possible Suspicions:

Network-level restrictions (e.g., DNS, NSG, firewall)

Redis Private Endpoint misconfiguration

• Incorrect TLS setupRedis connection from our Azure Virtual Machine to Azure Managed Redis is frequently failing. The VM is unable to maintain a stable connection—either timing out or getting disconnected shortly after connecting. All credentials and configurations appear to be correct. Steps to Reproduce:
  1. Connect to Azure VM (Linux/Windows).
  2. Use redis-cli or application to connect to Azure Managed Redis:
     • Host: <your-redis-name>.redis.cache.windows.net
     • Port: 6380 (TLS)
     • Password: (Access key from Azure portal)
  3. Run any Redis command or keep the connection idle.
  Expected Result:
  A stable and persistent connection to the Redis instance, allowing commands to be executed normally. Actual Result:
  Connection either:
  • Fails immediately with error:
    • (error) WRONGPASS invalid username-password pair
    • Could not connect to Redis at <host>:6379: Connection refused
  • Or disconnects after a short time
  Environment Details:
  • Azure VM OS: [e.g., Ubuntu 20.04 / Windows Server 2022]
  • Redis Client: redis-cli / StackExchange.Redis / custom app
  • Redis Hostname: <your-redis-host>.redis.cache.windows.net
  • Port: 6380
  • TLS: Enabled
  • Network Security Group: Port 6380 outbound allowed
  • DNS Resolution: Working from VM
  Troubleshooting Done:
  • Verified Redis credentials from Azure portal
  • Ensured VM outbound rules allow port 6380
  • Tested with and without TLS
  • Attempted from different VMs
  Possible Suspicions:
  • Network-level restrictions (e.g., DNS, NSG, firewall)
  • Redis Private Endpoint misconfiguration
  • Incorrect TLS setup