@auricio We are sorry to hear that you are having issues with access token. Looks like your access token is expired.
Did you follow the instructions at this tutorial: https://github.com/Azure-Samples/blockchain/tree/master/blockchain-workbench/auth-samples for getting the token?
You can use the Rest API samples to interact with Workbench APIs: https://github.com/Azure-Samples/blockchain/tree/master/blockchain-workbench/rest-api-samples
As per you query, if you are trying to access our API programmatically you can create a service a service principal to access work bench API and by using an AAD library (available in many languages) to generate the bearer token. Here an example for NodeJS
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