-----BEGIN BITCOIN SIGNED MESSAGE-----
In order to sign the signature, try to copy spaces and empty lines from the browser via autocorrect.
or delete the empty lines, and replace your spaces with spaces from the browser
-----BEGIN SIGNATURE-----
12e27iWAfBzLCe5U2FTovQVQ52G6FTkdCP
HKHvtLgO51qW6IfREZsVQF7hZmZlAt4GLTTuVz3fLUzuUSYEFAHA6Ph7uDKlhx0IUiXYwgd7DdREcGm/gZ+Y7c0=
-----END BITCOIN SIGNED MESSAGE-----