I tried your link. The reason it's failing is because it apparently doesn't support SegWit addresses. If you enter the Bitcoin address, message, and signature using
this link, however, you'll see it verifies just fine:
https://www.verifybitcoinmessage.com/Set the Bitcoin address field to:
bc1qhsfpjh8e9rhu90e9s2swt84g979vaaz8upyrqq
Set the Message field to :
juan_more_bitcoin is proving ownership of address:
bc1qhsfpjh8e9rhu90e9s2swt84g979vaaz8upyrqq
hello, world
Set the Signature field to:
IEp63RLo+8FS8O24sMIAXirUnx5H4/HJycptd1drRwnMSC4axaxyrLWd5ACU9+obFIIMi9oKYiYWTbBehAQ5h90=
You'll see that it works.
Now... If you really want to use BrainWallet to verify it, you can get a verification by pasting in this alternate format:
-----BEGIN BITCOIN SIGNED MESSAGE-----
juan_more_bitcoin is proving ownership of address:
bc1qhsfpjh8e9rhu90e9s2swt84g979vaaz8upyrqq
hello, world
-----BEGIN SIGNATURE-----
IEp63RLo+8FS8O24sMIAXirUnx5H4/HJycptd1drRwnMSC4axaxyrLWd5ACU9+obFIIMi9oKYiYWTbBehAQ5h90=
-----END BITCOIN SIGNED MESSAGE-----
You'll get the "message verified" success code but again, since it doesn't understand SegWit/Bech32 addresses, it spits back an incorrect Bitcoin address in the success message.