Python sdk copy blob from container to container

I hope somebody can help with this issue which is confusing me a bit.

I am trying to make a back up copy script for a storage container. What I am trying to achieve, is to copy the content of a container from container A to container B.

Just to make my case scenario clear, this is the structure of my storages.

Storage A:

storageaccountout 
 |--- Containers
   |---- new blob
     |---newfile.txt

In Storage account A I have a container called newblob and in this blob I have just one file.

On the other had I have storage B

Storage B:

Storageaccountin
  |--- Containers
    

Storage B has nothing, just the default blob $logs

What I am trying to do, is to copy the container A blob, into container B blob.

I have this script:

from azure.storage.blob import BlobClient, BlobServiceClient
from azure.storage.blob import ResourceTypes, AccountSasPermissions
from azure.storage.blob import generate_account_sas    
from datetime import *


# Source Client
connection_string = 'connection.string' # The connection string for the source container
account_key = 'key' # The account key for the source container
source_container_name = 'newblob' # Name of container which has blob to be copied
blob_name = 'lastfile.txt' # Name of the blob you want to copy
destination_container_name = 'incontainer' # Name of container where blob will be copied


# Target Client
target_connection_string = 'connection-string'
target_account_key = 'key'
source_container_name = source_container_name
target_blob_name = 'newfile.txt'
target_destination_blob = 'newblob'
# Create client
client = BlobServiceClient.from_connection_string(connection_string) 

# Create target client
target_client = BlobServiceClient.from_connection_string(target_connection_string)

# Create sas token for blob
sas_token = generate_account_sas(
    account_name = client.account_name,
    account_key = account_key, 
    resource_types = ResourceTypes(object=True, container=True),
    permission= AccountSasPermissions(read=True,list=True),
    # start = datetime.now(),
    expiry = datetime.utcnow() + timedelta(hours=4) # Token valid for 4 hours
)

# Create blob client for source blob
source_blob = BlobClient(
    client.url,
    container_name = source_container_name, 
    blob_name = blob_name,
    credential = sas_token
)


# target client

target_sas_token = generate_account_sas(
    account_name = target_client.account_name,
    account_key = target_account_key, 
    resource_types = ResourceTypes(object=True, container=True),
    permission= AccountSasPermissions(read=True,list=True),
    # start = datetime.now(),
    expiry = datetime.utcnow() + timedelta(hours=4) # Token valid for 4 hours
)

# Create blob client for source blob
source_blob = BlobClient(
    target_client.url,
    container_name = source_container_name, 
    blob_name = target_blob_name,
    credential = target_sas_token
)

# Create new blob and start copy operation.
# new_blob = client.get_blob_client(destination_container_name, blob_name)    
new_blob = client.get_blob_client(target_destination_blob, target_blob_name)    
new_blob.start_copy_from_url(source_blob.url)

Now When I run this script, I get the following error:

Traceback (most recent call last):
  File "/Users/user/miniforge3/lib/python3.9/site-packages/azure/storage/blob/_blob_client.py", line 1922, in start_copy_from_url
    return self._client.blob.start_copy_from_url(**options)
  File "/Users/user/miniforge3/lib/python3.9/site-packages/azure/storage/blob/_generated/operations/_blob_operations.py", line 2280, in start_copy_from_url
    raise HttpResponseError(response=response, model=error)
azure.core.exceptions.HttpResponseError: Operation returned an invalid status 'Server failed to authenticate the request. Make sure the value of Authorization header is formed correctly including the signature.'

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/Users/user/Desktop/AzCopy/blob.py", line 35, in <module>
    new_blob.start_copy_from_url(source_blob.url)
  File "/Users/user/miniforge3/lib/python3.9/site-packages/azure/core/tracing/decorator.py", line 83, in wrapper_use_tracer
    return func(*args, **kwargs)
  File "/Users/user/miniforge3/lib/python3.9/site-packages/azure/storage/blob/_blob_client.py", line 1924, in start_copy_from_url
    process_storage_error(error)
  File "/Users/user/miniforge3/lib/python3.9/site-packages/azure/storage/blob/_shared/response_handlers.py", line 150, in process_storage_error
    error.raise_with_traceback()
  File "/Users/user/miniforge3/lib/python3.9/site-packages/azure/core/exceptions.py", line 247, in raise_with_traceback
    raise super(AzureError, self).with_traceback(self.exc_traceback)
  File "/Users/user/miniforge3/lib/python3.9/site-packages/azure/storage/blob/_blob_client.py", line 1922, in start_copy_from_url
    return self._client.blob.start_copy_from_url(**options)
  File "/Users/user/miniforge3/lib/python3.9/site-packages/azure/storage/blob/_generated/operations/_blob_operations.py", line 2280, in start_copy_from_url
    raise HttpResponseError(response=response, model=error)
azure.core.exceptions.ResourceNotFoundError: Server failed to authenticate the request. Make sure the value of Authorization header is formed correctly including the signature.
RequestId:199c7c8a-501e-00a3-7418-aed966000000
Time:2021-09-20T12:08:20.0231825Z
ErrorCode:CannotVerifyCopySource
Error:None

As far as I understand, this is an error with the Share Access Signature, but how is this working if I am giving the connection string and the storage key, how come I am getting this error.

Thank you so much for any help you can provide me with and please, if you need more info do not hesitate to ask