Sufficient funds to send, but NEXT button greyed out

I have 0,02 ETH in my MetaMask account. I want to send it either the ENJIN wallet or KuCoin. I get the address, I choose max amount of ETH, but the NEXT button stays greyed out.
I tried reducing the amount of ETH to sending only half, but the result is the same. Gas cost is around 2$ right now.
How to I get my ETH out of my Metamask account? Thanks for any help.