Quote from: ManagerVirta on March 25, 2018, 09:39:19 PM

-----BEGIN BITCOIN SIGNED MESSAGE-----
Date: 25/03/2018, Sunday. My bitcointalk profile: https://bitcointalk.org/index.php?action=profile;u=868760
Sunday. I'm ManagerVita, own this address.
-----BEGIN SIGNATURE-----
3GMfvcUCRrXF6HYFq87b2KoM4zSN8eN5Fd
JC4Zj5Dnht7YjYCOCOsblD0bu9/RN1yT6E7Lmbk0Vtc1CvvrwJLLkL5U+UqZ8RcxtkDFXaeyqCy5OXTYWjvQw+s=
-----END BITCOIN SIGNED MESSAGE-----

I tried with brainwalletx and Electrum but both failed to verify. Try signing new signature without new line. Line break sometimes causes troubles. And verify it yourself with https://brainwalletx.github.io/#verify if it works, it should work for me as well.