The error means there is issue either the image is not there or the credential is not correct for the docker repo. It could also mean missing tag in Image field.
Can you look into the ACI events and see if you find some more information on the error?
To isolate the issue, can you please try to create container from docker command and login with same credential and parameter you are using in ACI ?
can you please try to add tag latest to the image like :latest or :v1
To deploy to ACI from a private Docker Hub repository, the Image registry login server must be index.docker.io.
Here is a similar issue for your reference that can help troubleshoot.
Few other References:
Hope this information is helps in solving your issue.
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