Can't swap Hex to ETH even that enough ETH is on my account

Hello community,

For some reason I can’t swap my HEX to ETH even that there is enough ETH on my account.
I always get the note that … more ETH is needed to do the swap.
But I have swapped HEX into ETH twice in the past 2 weeks without any problems.
Please help.

Thanks a lot in advance.
cheers Brini