Unable to solve JSchException: Auth cancel Error

Question

I have a Ktor server, and I want to deploy it on a VPS. I generated public and private keys in my system, also added the public key to the VPS SSH,

Now in my server code I wrote some script in my build.gradle file to deploy the server directly to my VPS.

In build.gradle

val sshAntTask = configurations.create("sshAntTask")

ant.withGroovyBuilder {
    "taskdef"(
        "name" to "scp",
        "classname" to "org.apache.tools.ant.taskdefs.optional.ssh.Scp",
        "classpath" to configurations.get("sshAntTask").asPath
    )
    "taskdef"(
        "name" to "ssh",
        "classname" to "org.apache.tools.ant.taskdefs.optional.ssh.SSHExec",
        "classpath" to configurations.get("sshAntTask").asPath
    )
}


 task("deploy") {
    dependsOn("clean", "shadowJar")
    ant.withGroovyBuilder {
        doLast {
            val knownHosts = File.createTempFile("knownhosts", "txt")
            val user = "root"
            val host = "server_ip" //here I have my VPS server's IP
            val key = file("keys/prvtkey") //this file is present in the mentioned directory
            val jarFileName = "myfile.jar"
            try {
                "scp"(
                    "file" to file("build/libs/$jarFileName"),
                    "todir" to "$user@$host:/root/serverFiles",
                    "keyfile" to key,
                    "trust" to true,
                    "knownhosts" to knownHosts
                )
                "ssh"(
                    "host" to host,
                    "username" to user,
                    "keyfile" to key,
                    "trust" to true,
                    "knownhosts" to knownHosts,
                    "command" to "mv /root/serverFiles/$jarFileName /root/serverFiles/myfile.jar"
                )
                ...

I have this above code which doesn't have any errors. When I run the command in Android Studio's terminal ./gradlew this works fine with no error as it just runs the Gradle tasks

But when I run the command ./gradlew deploy I got error as Auth Cancel

I have attached a screenshot of what I'm getting in terminal.

For clarity I have this prvtkey (the SSH private key) in my project, which is mentioned in code. Also I have added the public key to my VPS SSH's

If you think the connection to this IP might not be working then I tried this command.

ssh root@*my_server_ip* OR ssh -i prvtkey root@*my_server_ip* also works
//asks for password 
//then connection establishes

I think I haven't have any password or something to Authenticate to Server, maybe thats the reason for this error but I have private and public key to do that part but it doesn't works. If I'm correct then suggest a solution, or correct me if I'm wrong, as I am new to Ktor and also in VPS server hosting Terminal screenshot

[EDIT]

When i test the connection using terminal opened in .ssh directory

ssh -t prvtkey root@server_ip //this works without password

but when i tested the same command from the project directory's keys/prvtkey i got error for file permissions and it asks for password

Now I have corrected that and also tested the connection from the project

ssh -i keys/tictackey root@server_ip //now it goes well without password

The error remains the same This Might help you to understand the keys configs