Error when run with smartfoxserver lib

Unexpected failure to resolve a method: void com.smartfoxserver.v2.protocol.binary.DefaultPacketEncrypter.()
dex2oat F 836 83766 /Volumes/SSD/gh-moe-master-1.3.0-beta-2/aosp/art/compiler/oat_writer.cc:655] java.lang.NoClassDefFoundError: com.smartfoxserver.v2.protocol.binary.DefaultPacketEncrypter.

How to resolve it?

I add -keep class com.smartfoxserver.v2.protocol.binary.DefaultPacketEncrypter to proguard.append.cfg but not OK.

Pls help me!