Shopify support reply:
Haddin here with Shopify Retail Support, thank you for reaching out today!
Our team is currently aware of an issue affecting the current app version (5.45), and our developers are working as quickly as possible to release a fix for these connection issues. At the moment, this issue seems to only happen after allowing a single transaction to be printed. Once the printer stops responding:
In addition to the above steps, please be sure to regularly check for app updates as we work to release a fix, and install any update as soon as they become available. You can also enable automatic app updates on your device to ensure you download and install the latest version as soon as it becomes available.