Botocore fails to read credentials when run as daemon.service

I had my script running smoothly from command line, however, when I start it as a systemd.service, I get the following error:

iot_local.service - My iot_local Service
   Loaded: loaded (/lib/systemd/system/iot_local.service; enabled; vendor preset: enabled)
   Active: failed (Result: exit-code) since Sun 2018-04-01 23:06:45 UTC; 5s ago
  Process: 2436 ExecStart=/usr/bin/python /home/ubuntu/myTemp/iot_local.py (code=exited, status=1/FAILURE)
 Main PID: 2436 (code=exited, status=1/FAILURE)

Apr 01 23:06:45 ip-172-31-29-45 python[2436]:   File "/usr/local/lib/python2.7/dist-packages/botocore/client.py", line 358, in resolve
Apr 01 23:06:45 ip-172-31-29-45 python[2436]:     service_name, region_name)
Apr 01 23:06:45 ip-172-31-29-45 python[2436]:   File "/usr/local/lib/python2.7/dist-packages/botocore/regions.py", line 122, in construct_endpoint
Apr 01 23:06:45 ip-172-31-29-45 python[2436]:     partition, service_name, region_name)
Apr 01 23:06:45 ip-172-31-29-45 python[2436]:   File "/usr/local/lib/python2.7/dist-packages/botocore/regions.py", line 135, in _endpoint_for_partition
Apr 01 23:06:45 ip-172-31-29-45 python[2436]:     raise NoRegionError()
Apr 01 23:06:45 ip-172-31-29-45 python[2436]: botocore.exceptions.NoRegionError: You must specify a region.
Apr 01 23:06:45 ip-172-31-29-45 systemd[1]: iot_local.service: Main process exited, code=exited, status=1/FAILURE
Apr 01 23:06:45 ip-172-31-29-45 systemd[1]: iot_local.service: Unit entered failed state.
Apr 01 23:06:45 ip-172-31-29-45 systemd[1]: iot_local.service: Failed with result 'exit-code'.

it seems to fail on this line:

DB=boto3.resourse('dynamodb')

If I add the region as an argument, the script still fails later because can not find credentials. So, when I provide region, id and a key as argument, everything works:

boto3.resource('dynamodb', region_name='us-west-2', aws_access_key_id=ACCESS_ID, aws_secret_access_key=ACCESS_KEY)

The obvious problem is that when this script is run as service, it fails to obtain the info from the ~/.aws/config and ~/.aws/credentials, which I made sure to contain all the necessary information by running aws configure as mentioned here.

[default]
aws_access_key_id=XXXXXXXXXXXXXX
aws_secret_access_key=YYYYYYYYYYYYYYYYYYYYYYYYYYY

I also tried this:

export AWS_CONFIG_FILE="/home/ubuntu/.aws/config"

and this

sudo chown root:root ~/.aws

but it did not help. Any ideas why .service does not "see" the credentials files?