This problem is an ongoing one. It's been happening for years. I've had the same issue on multiple devices, and with multiple browsers, with multiple accounts .
From what I can tell, optus has tried to fix the problem by creating a new my account page .When you log in, it should go to this new page (3 vertical loading bars), but for some reason it still gets directed to the old page (circle spinner loading bars), which no longer has access to the server, because it's obsolete.
You can get it to direct to the new page, but it loops endlessly .
I can honestly say that this problem SHOULD BE FIXED AS AN ABSOLUTE PRIORITY, AND AT WHATEVER COST .
We pay enough for our service that a working account web page should be a given. We've been waiting for years for a fix for this, and IT IS NOT GOOD ENOUGH OPTUS.