@Fares I told you to check action server log, whilst using rasa run actions --debug as custom action run using rasa run actions, and no worries, since few days me really busy.
You should use message.get("text_tokens")
instead of message.get("tokens")
TOKENS_NAMES = {
rasa.shared.nlu.constants.TEXT: "text_tokens",
rasa.shared.nlu.constants.INTENT: "intent_tokens",
rasa.shared.nlu.constants.RESPONSE: "response_tokens",
rasa.shared.nlu.constants.ACTION_NAME: "action_name_tokens",
rasa.shared.nlu.constants.ACTION_TEXT: "action_text_tokens",
rasa.shared.nlu.constants.INTENT_RESPONSE_KEY: "intent_response_key_tokens",
}