This sounds like an issue with your setup. What cards do you have? You're mining which coins?

Yeah averages don't always work out in mining over a short period. Lot of variance.

Over what period of time? In case you are not aware, rewards are given only for the blocks the pool finds. There was no block found by the pool for 3 days now.

Got an echo that a new dashboard update will be released soon that should fix this.

I have absolutely no confident answer for you. It's definitely a local problem at your end. Do you get the 404 even if you open the page in a Private/Incognito window mode?

Can you open up your browser's console (CTRL+SHIFT+i on Windows for both Firefox and Chrome, Console tab) and try opening the page again. What errors are you getting? 

And  your wallet address?

No issue for me

Rewards are distributed only after confirmation. So you have to wait.

For the past 1 day there was only 1 block found couple minutes ago, so as mentioned below, we just had a bad luck. The effort is quite high, so don't expect to be rewarded for all your shares.