I need some help please! I keep getting ERR_CONNECTION_TIME_OUT when trying to access MyIR - which is kind of vital as a contract accountant to be able to access!

I've got my Macbook Air and my HP Probook. I use both of these for work, albeit for two different jobs. Between both laptops, different browsers (chrome, edge & safari) I'm having the same issue and I've ruled these out. I have spark fibre at home, and this is where I work 50% of the time. The remainder of my office hours are 40 minutes up the road, with Vodafone fibre in the office.

Accessing MyIR works great on vodafone fibre and on my vodafone hotspot. However, I cannot for the life of me, access it from my spark fibre connection, which leads me to think its Spark Fibre (for some reason my S22 ultra refuses to be a good phone and hotspot, another issue for another day)

I spoke with my account manager at the IRD and she said there is *some* overloading on MyIR at present, but I'm not seeing any signs of it when using VF and I doubt that it would be overloaded at 11pm on Saturday night.

After process of elimination, its lead me to believe its my spark fibre.

Does anyone have any ideas on what I can do to try and fix this? I've had to turn down some contract jobs this week as a result and I'm wondering if I need to change ISP. FWIW my modem/router is the standard Spark Smart Modem, wifi APs are Unifi AR etc, not that that matters. i can't even spot where to change the DNS settings in the admin portal for the modem to try that as an option :(

Open to any and all ideas, and yes I'm trying to contact Spark again via their normal channels.