Hi @Robert_Ackroyd,
Thanks for confirming the other PC is working as expected. Since this issue is tied to just the QNAP, I would investigate further in this direction:
- Have you made any changes to the QNAP software/firmware since it was working vs now?
- Are you using the latest QNAP build? There was an issue that was addressed a couple of days ago with QNAP, please see here:
- What is your network setup like? Is the QNAP connected directly to the router or though a switch/range extender/powerline adapter? I would try connecting directly to the router and bypass any additional networking gear if you have any as a test.