Unable to Merg dex

[khan1hamdan]

Error:Execution failed for task ':app:transformDexArchiveWithExternalLibsDexMergerForDebug'.

com.android.builder.dexing.DexArchiveMergerException: Unable to merge dex

[khan1hamdan]

I apply all methods which is shown on stackoverflow and my gradle have no jar file but get same error when i insert this library