I am using Docker Connector to try to cache mcr.microsoft.com, gcr.io and hub.docker.com images.
I was able to successfully cache the image of mcr and hub, but when I added the connector of gcr and tried to pull the image from the feed, I got error.

When I pull the image from gcr, I got an error:

# docker pull myproget/gcr/kaniko-project/executor:v1.6.0-debug
v1.6.0-debug: Pulling from gcr/kaniko-project/executor
981fc7edb8fd: Pulling fs layer
d044254b2a54: Pulling fs layer
8f137c16aecd: Pulling fs layer
6566d8138b04: Waiting
3d8068545002: Waiting
fe2d5f51c3f2: Waiting
ee2c784f1c11: Waiting
13e1a61a0623: Waiting
ddd1314b2f82: Waiting
1e1b51c21c3c: Waiting
error pulling image configuration: unknown blob

At this time, I can see the following warning message on the management interface:

Connector: #3 Google Container Registry (https://gcr.io/)
Blob requested: kaniko-project/executor:sha256:d044254b2a54234cc1cc99f99e20b921714376e4139f6933f41b266b90675635
Full exception:
System.Net.WebException: The remote server returned an error: (400) Bad Request.
at Inedo.ProGet.Feeds.Docker.DockerException.TryThrow(Exception innerException, Int32 statusCode, String body) in ...\Src\ProGetCoreEx\Feeds\Docker\DockerException.cs:line 108
at Inedo.ProGet.Feeds.Docker.DockerConnector.GetDirectResponseAsync(String url) in ...\Src\ProGetCoreEx\Feeds\Docker\DockerConnector.cs:line 209
at Inedo.ProGet.Feeds.Docker.DockerConnector.GetBlobAndMediaTypeAsync(DockerRepositoryName repositoryName, DockerDigest digest) n ...\Src\ProGetCoreEx\Feeds\Docker\DockerConnector.cs:line 113
at Inedo.ProGet.WebApplication.SimpleHandlers.Docker.DockerHandler.ProcessBlobAsync(HttpContext context, DockerFeed feed, String repositoryName, String reference) in ...\Src\ProGet.WebApplication\SimpleHandlers\Docker\DockerHandler.cs:line 271

No, this is a new deployment. And health check errors only occur on the connectors of Docker Hub and GCR, while Quay and MCR are work final.
At the same time, I can pull the image directly from gcr.io.

Today I found another problem. Connectors health check reports docker hub, gcr and k8s gcr check errors.
The error message looks like there is Unauthorized, but docker hub and gcr should be public registry. Why does the health check require authentication and how to eliminate this error?

Connector Docker Hub health check reported error: The remote server returned an error: (401) Unauthorized.

I use Version 5.3.33 (Build 9) by Docker.

I am using Docker Connector to try to cache mcr.microsoft.com, gcr.io and hub.docker.com images.
I was able to successfully cache the image of mcr and hub, but when I added the connector of gcr and tried to pull the image from the feed, I got error.

When I pull the image from gcr, I got an error:

# docker pull myproget/gcr/kaniko-project/executor:v1.6.0-debug
v1.6.0-debug: Pulling from gcr/kaniko-project/executor
981fc7edb8fd: Pulling fs layer
d044254b2a54: Pulling fs layer
8f137c16aecd: Pulling fs layer
6566d8138b04: Waiting
3d8068545002: Waiting
fe2d5f51c3f2: Waiting
ee2c784f1c11: Waiting
13e1a61a0623: Waiting
ddd1314b2f82: Waiting
1e1b51c21c3c: Waiting
error pulling image configuration: unknown blob

At this time, I can see the following warning message on the management interface:

Connector: #3 Google Container Registry (https://gcr.io/)
Blob requested: kaniko-project/executor:sha256:d044254b2a54234cc1cc99f99e20b921714376e4139f6933f41b266b90675635
Full exception:
System.Net.WebException: The remote server returned an error: (400) Bad Request.
at Inedo.ProGet.Feeds.Docker.DockerException.TryThrow(Exception innerException, Int32 statusCode, String body) in ...\Src\ProGetCoreEx\Feeds\Docker\DockerException.cs:line 108
at Inedo.ProGet.Feeds.Docker.DockerConnector.GetDirectResponseAsync(String url) in ...\Src\ProGetCoreEx\Feeds\Docker\DockerConnector.cs:line 209
at Inedo.ProGet.Feeds.Docker.DockerConnector.GetBlobAndMediaTypeAsync(DockerRepositoryName repositoryName, DockerDigest digest) n ...\Src\ProGetCoreEx\Feeds\Docker\DockerConnector.cs:line 113
at Inedo.ProGet.WebApplication.SimpleHandlers.Docker.DockerHandler.ProcessBlobAsync(HttpContext context, DockerFeed feed, String repositoryName, String reference) in ...\Src\ProGet.WebApplication\SimpleHandlers\Docker\DockerHandler.cs:line 271