I tried on leafpool. Login to pool successful, but then messages like
[ERRO] [2019-01-08T20:36:13+01:00] Failed to parse the response: %!s(*stratum.RawIncomingMessage=0xc042152dd0), error: json: cannot unmarshal number -22 into Go struct field .code of type uint
[ERRO] [2019-01-08T20:36:16+01:00] Failed to parse the response: %!s(*stratum.RawIncomingMessage=0xc0421767d0), error: json: cannot unmarshal number -22 into Go struct field .code of type uint
[ERRO] [2019-01-08T20:36:16+01:00] Failed to parse the response: %!s(*stratum.RawIncomingMessage=0xc042152e80), error: json: cannot unmarshal number -22 into Go struct field .code of type uint
cannot unmarshal number -22 into Go struct field .code of type uint
forever

I tried it with just worker and and with worker name and email while replacing @ and / with corresponding special characters in URI format