Shopify public app authentication token expiry

[DebashisD]

I am developing a shopify public application which is fetching the authentication token from the shopify store. but it is getting expired automatically after few hours so the subsequent API calls give an error is there any way to generate the auth token without opening the application or use the token for a longer period of time. 

[Fabrice3]

Hi there,

Have a look here, faced the same issue...

https://community.shopify.com/c/Technical-Q-A/API-Invalid-API-key-or-access-token-unrecognized-login...