application crashes when invalid market is added

[rgf2004]

applications crashes with exception
de.elbatya.cryptocoins.bittrexclient.api.model.common.BittrexApiException: Message from Bittrex server: INVALID_MARKET
at de.elbatya.cryptocoins.bittrexclient.api.model.common.ApiResult.unwrap(ApiResult.java:40) ~[bittrex-java-client-v2.0.jar!/:na]
at com.github.stoploss.core.exchange.BittrexExchange.getCurrentPrice(BittrexExchange.java:44) ~[classes!/:0.0.1-SNAPSHOT]
at com.github.stoploss.core.StopLossEngine.getPriceByMarketName(StopLossEngine.java:49) [classes!/:0.0.1-SNAPSHOT]
at java.util.stream.ReferencePipeline$3$1.accept(ReferencePipeline.java:193) ~[na:1.8.0_151]
at java.util.HashMap$KeySpliterator.forEachRemaining(HashMap.java:1553) ~[na:1.8.0_151]
at java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:481) ~[na:1.8.0_151]
at java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:471) ~[na:1.8.0_151]
at java.util.stream.ReduceOps$ReduceOp.evaluateSequential(ReduceOps.java:708) ~[na:1.8.0_151]