Terraform settings - remote state s3 - InvalidParameter validation error - terraform

Question

Environment
Terraform v0.12.24
+ provider.aws v2.61.0
Running in an alpine container.
Background
I have a basic terraform script running ok, but now I'm extending it and am trying to configure a remote (S3) state.
terraform.tf:
terraform {
backend "s3" {
bucket = "labs"
key = "com/company/labs"
region = "eu-west-2"
dynamodb_table = "labs-tf-locks"
encrypt = true
}
}
The bucket exists, and so does the table. I have created them both with terraform and have confirmed through the console.
Problem
When I run terraform init I get:
Error refreshing state: InvalidParameter: 2 validation error(s) found.
- minimum field size of 1, GetObjectInput.Bucket.
- minimum field size of 1, GetObjectInput.Key.
What I've tried
terraform fmt reports no errors and happily reformats my terraform.tf file. I tried moving the stanza into my main.tf too, just in case the terraform.tf file was being ignored for some reason. I got exactly the same results.
I've also tried running this without the alpine container, from an ubuntu ec2 instance in aws, but I get the same results.
I originally had the name of the terraform file in the key. I've removed that (thanks) but it hasn't helped resolve the problem.
Also, I've just tried running this in an older image: hashicorp/terraform:0.12.17 but I get a similar error:
Error: Failed to get existing workspaces: InvalidParameter: 1 validation error(s) found.
- minimum field size of 1, ListObjectsInput.Bucket.
I'm guessing that I've done something trivially stupid here, but I can't see what it is.

Answer 1

Solved!!!
I don't understand the problem, but I have a working solution now. I deleted the .terraform directory and reran terraform init. This is ok for me because I don't have an existing state. The insight came from reading the error from the 0.12.17 version of terraform, which complained about not being able to read the workspace.
Error: Failed to get existing workspaces: InvalidParameter: 1 validation error(s) found.
- minimum field size of 1, ListObjectsInput.Bucket.
Which initially led me to believe there was a problem with an earlier version of tf reading a newer version's configuration. So, I blew away the .terraform and it worked with the older tf, so I did it again and it worked with the newer tf too. Obviously, something had gotten itself screwed up in terraform's storage. I don't know how or why. But, it works for me, so...

Answer 2

If you are facing this issue in app side, there is a chance that you are sending a wrong payload or the payload is updated by the backend.
Before i was doing this->
--> POST .../register
{"email":"FamilyKalwar#gmail.com","user":{"password":"123456#aA","username":"familykalwar"}}
--> END POST (92-byte body)
<-- 500 Internal Server Error .../register (282ms)
{"message":"InvalidParameter: 2 validation error(s) found.\n- minimum field size of 6, SignUpInput.Password.\n- minimum field size of 1, SignUpInput.Username.\n"}
Later I found that the payload is updated to this->*
{
"email": "tanishat1#gmail.com",
"username": "tanishat1",
"password": "123456#aA"
}
I removed the "user" data class and updated the payload and it worked!