According to Shopify Support Team, Shopify's API access tokens for merchants using the client credentials grant will expire every 24 hours starting January 2026.
And Legacy custom app connections still rely on static API access tokens and secret keys without a refresh flow.
Since the Acumatica public app uses OAuth for authentication, the token refresh mechanism would typically be part of the OAuth flow, however, the available Acumatica documentation and Shopify release notes do not detail any Shopify-specific token refresh implementation on the connector side.
Please confirm whether the Acumatica connector handles the 24-hour token refresh automatically or if manual intervention is required.