Same problem! I met this sometimes but I don't know why. At first, I think it's because of the website https://www.oneday.co.th/ was slow. But it was loaded on other platforms like Edge or Chrome.

P/s: My Internet was totally fine as well
Included Speed test: image (I can't upload the image directly)

@hongkongkidemy Thanks, it was solved

I got the same error when using Opera to login this page:
https://www.oneday.com.vn/

I'm just a user, so I don't know how to get the version of my current Opera but my device is: Iphone 8 plus.

It seems nobody replied how to resolve this issue. Please help us!