Here are several of the errors I get when using Realms:

Internal Exception: io.netty.handler.codec.DecoderException: java.util.zip.DataFormatException: incorrect header check
Internal Exception: io.netty.handler.codec.DecoderException: Badly compressed packet - size of 1531896730 is larger than protocol maximum of 2097152
Internal Exception: io.netty.handler.codec.CorruptedFrameException: length wider than 21-bit
Internal Exception: io.netty.handler.codec.DecoderException: java.util.zip.DataFormatException: incorrect header check
Internal Exception: io.netty.handler.codec.CorruptedFrameException: length wider than 21-bit (I know, this one repeated, they do that too)
Internal Exception: io.netty.handler.codec.DecoderException: Badly compressed packet - size of 11478809 is larger than protocal maximum of 2097152
Internal Exception: io.netty.handler.codec.DecoderException: Badly compressed packet - size of 102 is below server threshold of 256

attatched is my crash report