Docker Push to Azure Container Registry always fails on authentication regardless

Question

Docker Push to Azure Container Registry always fails on authentication regardless

David Hirst 20

I am trying to push an image from docker to an ACR.

Regardless of what I try, I am constantly told that the request is unauthenticated, despite being given successful login messages when I authenticate prior to making the push.

I have tried the following:

az login
az acr login --name myacrname

docker tag localImageName:<Tag> myacrname.azurecr.io/localImageName:<Tag>
docker push myacrname.azurecr.io/localImageName:<Tag>

It throws the following:

unauthorized: {"errors":[{"code":"UNAUTHORIZED","message":"authentication required, visit https://aka.ms/acr/authorization for more information. CorrelationId: 31ee7a50-xxxx-xxxx-xxxx-c1a7a530e786"}]}

I have tried this:

docker login -u acradmin -p acradminpassword myacrname
az login
az acr login --name myacrname -u acradmin -p acradminpassword

docker tag localImageName:<Tag> myacrname.azurecr.io/localImageName:<Tag>
docker push myacrname.azurecr.io/localImageName:<Tag>

I get the same error. I can confirm that my own user (that opens the CLI) has owner, acrpush and acrpull roles on the ACR and if I run an az acr repository command I get results back and if I do a docker pull it also works.

I have ran acr healh-check and it comes back clean. Nothing seems to work and all I seem to get is this message. What is wrong here?

Nikhil Duserla 8,515 Reputation points Microsoft External Staff Moderator

2025-07-04T17:20:48.5733333+00:00

Hello @David Hirst,

Checking to see whether you have resolved the issue with the solution provided above, or if you need any further assistance, please let us know. We are happy to help.
David Hirst 20 Reputation points

2025-07-07T09:27:33.5766667+00:00

The admin user is enabled and I have used the credentials there as well, its the same error.
Nikhil Duserla 8,515 Reputation points Microsoft External Staff Moderator

2025-07-09T14:20:21.32+00:00

Hello @David Hirst,

Did you try the solution provided above? It worked for me. If you're still experiencing the issue, please let us know. I'm happy to assist further.

3 answers

Your answer

Nikhil Duserla 8,515 Reputation points Microsoft External Staff Moderator

2025-07-04T17:20:48.5733333+00:00

Hello @David Hirst,

Checking to see whether you have resolved the issue with the solution provided above, or if you need any further assistance, please let us know. We are happy to help.
David Hirst 20 Reputation points

2025-07-07T09:27:33.5766667+00:00

The admin user is enabled and I have used the credentials there as well, its the same error.
Nikhil Duserla 8,515 Reputation points Microsoft External Staff Moderator

2025-07-09T14:20:21.32+00:00

Hello @David Hirst,

Did you try the solution provided above? It worked for me. If you're still experiencing the issue, please let us know. I'm happy to assist further.

Answer 1

Hello @David Hirst,
It appears you're encountering an authentication issue while attempting to push an image to Azure Container Registry (ACR). Still having Owner role to the Container Registry to push and pull images you have to enable the admin user. This generates a username, password, and password2.

Once enabled the admin user try log in now to Azure Container Registry using the command:

az acr login --name my-container-registry

Tag your docker image:

docker tag image-name:image-tag my-container-registry.azurecr.io/image-name:image-tag

And now push image to Azure Container Registry using the command:

docker push my-container-registry.azurecr.io/image-name:image-tag

Remove the docker login step from your build, docker tasks handle auth for you using azure subscription endpoint (if it is properly configured), if not - give your service principal permissions to acrpush).

Additionally, case sensitivity may lead to issues. When using its server url in docker commands, to avoid authentication errors, use all lowercase.

If you have any further queries, do let us know.

Answer 2

Hello @David Hirst,

Could you please share a screenshot of the issue via private message?

In the meantime, I’ve tested the same scenario in my lab environment and was able to successfully push a Docker image to Azure Container Registry (ACR). Please follow the steps below to ensure everything is set up correctly:

Create an Azure Container Registry (ACR) via the Azure portal.

Install Docker on your local machine if it’s not already installed.

Log in to ACR from the command line using:
```
   
   docker login <your-login-server>.azurecr.io
```
(Replace <your-login-server> with your actual ACR login server, e.g., mysetup.azurecr.io.)
Pull the hello-world image:
```
   docker pull hello-world
```

Tag the image for your ACR:

   
   docker tag hello-world:latest mysetup.azurecr.io/samples/hello-world:latest

Push the image to ACR:

   
   docker push mysetup.azurecr.io/samples/hello-world

User's image

Additionally, having below role assignments is required-

-> ACR Pull permissions are needed for login

-> ACR Push permissions are needed to push

-> After giving ACR Push permissions , try to re-login again

-> Wait for couple of mins to completely propagate the permissions

Let me know if you encounter any issues during these steps.

Answer 3

David Hirst 20

The above is not really an accepted answer, whilst the above instructions may work when you are using a new ACR they do not work, or I should did not work with the existing ACR we were trying to utilize. Regardless of which user account was used it simply throws this same authentication error each time a push is made. To me this is indicative a problem or bug with the container registry software used by Microsoft itself as a search online for a solution shows, as I am not the only person on the internet who seems to experience this issue with Azure.

To resolve our immediate problem we have had no choice but create a new ACR, copy the images from the old one to the new one and then to delete the original.

David Hirst 20

I tried the above instructions and they worked on a new ACR.

I then applied the same logic to the ACR I am trying to access and could not get past step 4, despite this using the admin user credentials for the ACR from the access settings page on the ACR.

Using default tag: latest The push refers to repository [myregistry.azurecr.io/samples/hello-world] 
9d7e6dd0c796: Preparing 
ffdb3e267000: Preparing 
44b913d145ad: Preparing 
unauthorized: {"errors":[{"code":"UNAUTHORIZED","message":"authentication required, visit https://aka.ms/acr/authorization for more information. CorrelationId: xxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxx"}]}

Nikhil Duserla 8,515 Reputation points Microsoft External Staff Moderator

2025-07-10T17:32:32.8+00:00

Hello @David Hirst ,

The error indicates authentication failed when accessing the ACR. This error can occur when running the az acr login or docker login command with an incorrect username and/or password, or expired credentials (when using a service principal, a token with a scope map, or an admin user).

Solution: Use the correct/valid username and password- https://learn.microsoft.com/en-us/troubleshoot/azure/azure-container-registry/acr-authentication-errors?source=recommendations#solution-use-the-correctvalid-username-and-password

If you have any further queries, do let us know.
David Hirst 20 Reputation points

2025-07-11T15:22:02.9833333+00:00

The above is not really an accepted answer, whilst the above instructions may work when you are using a new ACR they do not work, or I should did not work with the existing ACR we were trying to utilize. Regardless of which user account was used it simply throws this same authentication error each time a push is made. To me this is indicative a problem or bug with the container registry software used by Microsoft itself as a search online for a solution shows, as I am not the only person on the internet who seems to experience this issue with Azure.

To resolve our immediate problem we have had no choice but create a new ACR, copy the images from the old one to the new one and then to delete the original.
Nikhil Duserla 8,515 Reputation points Microsoft External Staff Moderator

2025-07-11T18:16:20.63+00:00

Hello @David Hirst,

I’m currently checking with our team regarding this issue. In the meantime, I’d request you to please share the requested details via private message.

Thank you!

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Docker Push to Azure Container Registry always fails on authentication regardless

3 answers

Your answer