I can not log into my account

This is the error message I receive:

JSON parse error: Unexpected character ('%' (code 37)): Expected space separating root-level values; nested exception is com.fasterxml.jackson.core.JsonParseException: Unexpected character ('%' (code 37)): Expected space separating root-level values at [Source: (PushbackInputStream); line: 1, column: 12]