I cannot accept some open challenges

Hello,

Sometimes when i try to accept an open challenge, it shows me a message: 

"You cannot accept this challenge at this moment."

Does someone know how can i solve this problem?

Maybe the challenger then started a game?

I repeatedly get this as well, it's unlikely that every time the problem is that the challenger started a game, it can happen 5 times in a row for me. I dont know what the problem is. Been happening for a while.

I'm getting the same thing.

Still having the issue as well, even member support is perplexed, theyre taking a while to answer but one thing they suggested (which didnt work for me but may work for someone else) is clearing the cache in your browser.

Clearing the cashe on my end and logging in again worked for me.

I logged in on a different browser, accepted a challenge there, then switched back to the original and it's fixed - at least for a few games.