Redux-Thunk Action setting action as Promise - reactjs

Question

So I'm using TS React, Redux, and Thunk middleware to handle redux actions that communicate with my api but I cant seem to get the initial configuration for my action function.
My action function is as follows:
export const startSession = ((accessCode: string) => {
return async (dispatch: Dispatch): Promise<Action> => {
try {
const response = await apiCall(accessCode);
return dispatch({ type: SessionActions.START_SESSION, payload: response });
} catch (e) {
console.log('error', e)
}
};
});
I have also tried this:
export const startSession = ((accessCode: string) => {
return async (dispatch: Dispatch) => {
try {
await apiCall(accessCode)
.then(response => dispatch({ type: SessionActions.START_SESSION, payload: response }))
} catch (e) {
console.log('error', e)
}
};
})
but neither seems to work. I thought waiting for the api response would force redux to wait, but it seems to be returning the promise into the state - shown in my redux-logger:
action undefined # 19:10:17.807
redux-logger.js?d665:1 prev state: {some state}
redux-logger.js?d665:1 action: Promise {<pending>}
And I get the error:
Uncaught Error: Actions must be plain objects. Use custom middleware for async actions.
I noticed that this dispatched type is undefined, so there must me a dispatch call being made initially before the data is returned from the api. If anyone could explain to me why it does this, and the standard format for writing actions that use thunk that would be super helpful.
Also please let me know if there is information that I'm missing.
Someone below asked to see how I the initialized store with thunk:
import { createStore, applyMiddleware } from 'redux';
import thunkMiddleware from 'redux-thunk';
import { createLogger } from 'redux-logger';
import { createBrowserHistory } from 'history';
import rootReducer from '../_reducers/index'
const loggerMiddleware = createLogger();
export const history = createBrowserHistory();
export const store = createStore(
rootReducer,
applyMiddleware(
thunkMiddleware,
loggerMiddleware
)
);