Client error - Could not send messagecom.fasterxml.jackson.core.JsonParseException: Unexpected character ('<' (code 60)): expected a valid value (JSON String, Number, Array, Object or token 'null', 'true' or 'false')
 at [Source: (StringReader); line: 1, column: 2]
	at com.fasterxml.jackson.core.JsonParser._constructError(JsonParser.java:1840)
	at com.fasterxml.jackson.core.base.ParserMinimalBase._reportError(ParserMinimalBase.java:712)
	at com.fasterxml.jackson.core.base.ParserMinimalBase._reportUnexpectedChar(ParserMinimalBase.java:637)
	at com.fasterxml.jackson.core.json.ReaderBasedJsonParser._handleOddValue(ReaderBasedJsonParser.java:1916)
	at com.fasterxml.jackson.core.json.ReaderBasedJsonParser.nextToken(ReaderBasedJsonParser.java:772)
	at com.fasterxml.jackson.databind.ObjectMapper._initForReading(ObjectMapper.java:4340)
	at com.fasterxml.jackson.databind.ObjectMapper._readMapAndClose(ObjectMapper.java:4189)
	at com.fasterxml.jackson.databind.ObjectMapper.readValue(ObjectMapper.java:3205)
	at com.fasterxml.jackson.databind.ObjectMapper.readValue(ObjectMapper.java:3173)
	at jenkins.plugins.rocketchatnotifier.rocket.RocketChatClientCallBuilder.buildPostCall(RocketChatClientCallBuilder.java:150)
Caused: jenkins.plugins.rocketchatnotifier.rocket.errorhandling.RocketClientException
	at jenkins.plugins.rocketchatnotifier.rocket.RocketChatClientCallBuilder.buildPostCall(RocketChatClientCallBuilder.java:152)
	at jenkins.plugins.rocketchatnotifier.rocket.RocketChatClientCallBuilder.buildCall(RocketChatClientCallBuilder.java:102)
	at jenkins.plugins.rocketchatnotifier.rocket.RocketChatClientImpl.sendSingleMessage(RocketChatClientImpl.java:178)
	at jenkins.plugins.rocketchatnotifier.rocket.RocketChatClientImpl.send(RocketChatClientImpl.java:149)
	at jenkins.plugins.rocketchatnotifier.rocket.RocketChatClientImpl.send(RocketChatClientImpl.java:142)
	at jenkins.plugins.rocketchatnotifier.rocket.RocketChatClientImpl.send(RocketChatClientImpl.java:136)
	at jenkins.plugins.rocketchatnotifier.RocketClientWebhookImpl.validate(RocketClientWebhookImpl.java:66)
	at jenkins.plugins.rocketchatnotifier.RocketChatNotifier$DescriptorImpl.doTestConnection(RocketChatNotifier.java:621)
	at java.lang.invoke.MethodHandle.invokeWithArguments(MethodHandle.java:627)
	at org.kohsuke.stapler.Function$MethodFunction.invoke(Function.java:396)
	at org.kohsuke.stapler.Function$InstanceFunction.invoke(Function.java:408)
	at org.kohsuke.stapler.Function.bindAndInvoke(Function.java:212)
	at org.kohsuke.stapler.Function.bindAndInvokeAndServeResponse(Function.java:145)
	at org.kohsuke.stapler.MetaClass$11.doDispatch(MetaClass.java:535)
	at org.kohsuke.stapler.NameBasedDispatcher.dispatch(NameBasedDispatcher.java:58)
	at org.kohsuke.stapler.Stapler.tryInvoke(Stapler.java:747)
	at org.kohsuke.stapler.Stapler.invoke(Stapler.java:878)
	at org.kohsuke.stapler.MetaClass$4.doDispatch(MetaClass.java:280)
	at org.kohsuke.stapler.NameBasedDispatcher.dispatch(NameBasedDispatcher.java:58)
	at org.kohsuke.stapler.Stapler.tryInvoke(Stapler.java:747)
	at org.kohsuke.stapler.Stapler.invoke(Stapler.java:878)
	at org.kohsuke.stapler.Stapler.invoke(Stapler.java:676)
	at org.kohsuke.stapler.Stapler.service(Stapler.java:238)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:790)
	at org.eclipse.jetty.servlet.ServletHolder.handle(ServletHolder.java:873)
	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1623)
	at hudson.util.PluginServletFilter$1.doFilter(PluginServletFilter.java:154)
	at org.jenkinsci.plugins.ssegateway.Endpoint$SSEListenChannelFilter.doFilter(Endpoint.java:246)
	at hudson.util.PluginServletFilter$1.doFilter(PluginServletFilter.java:151)
	at jenkins.security.ResourceDomainFilter.doFilter(ResourceDomainFilter.java:76)
	at hudson.util.PluginServletFilter$1.doFilter(PluginServletFilter.java:151)
	at io.jenkins.blueocean.ResourceCacheControl.doFilter(ResourceCacheControl.java:134)
	at hudson.util.PluginServletFilter$1.doFilter(PluginServletFilter.java:151)
	at io.jenkins.blueocean.auth.jwt.impl.JwtAuthenticationFilter.doFilter(JwtAuthenticationFilter.java:61)
	at hudson.util.PluginServletFilter$1.doFilter(PluginServletFilter.java:151)
	at jenkins.telemetry.impl.UserLanguages$AcceptLanguageFilter.doFilter(UserLanguages.java:128)
	at hudson.util.PluginServletFilter$1.doFilter(PluginServletFilter.java:151)
	at hudson.util.PluginServletFilter.doFilter(PluginServletFilter.java:157)
	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1610)
	at hudson.security.csrf.CrumbFilter.doFilter(CrumbFilter.java:99)
	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1610)
	at hudson.security.ChainedServletFilter$1.doFilter(ChainedServletFilter.java:84)
	at hudson.security.UnwrapSecurityExceptionFilter.doFilter(UnwrapSecurityExceptionFilter.java:51)
	at hudson.security.ChainedServletFilter$1.doFilter(ChainedServletFilter.java:87)
	at jenkins.security.ExceptionTranslationFilter.doFilter(ExceptionTranslationFilter.java:118)
	at hudson.security.ChainedServletFilter$1.doFilter(ChainedServletFilter.java:87)
	at org.acegisecurity.providers.anonymous.AnonymousProcessingFilter.doFilter(AnonymousProcessingFilter.java:125)
	at hudson.security.ChainedServletFilter$1.doFilter(ChainedServletFilter.java:87)
	at org.acegisecurity.ui.rememberme.RememberMeProcessingFilter.doFilter(RememberMeProcessingFilter.java:142)
	at hudson.security.ChainedServletFilter$1.doFilter(ChainedServletFilter.java:87)
	at org.acegisecurity.ui.AbstractProcessingFilter.doFilter(AbstractProcessingFilter.java:271)
	at hudson.security.ChainedServletFilter$1.doFilter(ChainedServletFilter.java:87)
	at jenkins.security.BasicHeaderProcessor.doFilter(BasicHeaderProcessor.java:93)
	at hudson.security.ChainedServletFilter$1.doFilter(ChainedServletFilter.java:87)
	at org.acegisecurity.context.HttpSessionContextIntegrationFilter.doFilter(HttpSessionContextIntegrationFilter.java:249)
	at hudson.security.HttpSessionContextIntegrationFilter2.doFilter(HttpSessionContextIntegrationFilter2.java:67)
	at hudson.security.ChainedServletFilter$1.doFilter(ChainedServletFilter.java:87)
	at hudson.security.ChainedServletFilter.doFilter(ChainedServletFilter.java:90)
	at hudson.security.HudsonFilter.doFilter(HudsonFilter.java:171)
	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1610)
	at org.kohsuke.stapler.compression.CompressionFilter.doFilter(CompressionFilter.java:49)
	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1610)
	at hudson.util.CharacterEncodingFilter.doFilter(CharacterEncodingFilter.java:82)
	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1610)
	at org.kohsuke.stapler.DiagnosticThreadNameFilter.doFilter(DiagnosticThreadNameFilter.java:30)
	at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1610)
	at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:540)
	at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:146)
	at org.eclipse.jetty.security.SecurityHandler.handle(SecurityHandler.java:524)
	at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:132)
	at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle(ScopedHandler.java:257)
	at org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:1700)
	at org.eclipse.jetty.server.handler.ScopedHandler.nextHandle(ScopedHandler.java:255)
	at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:1345)
	at org.eclipse.jetty.server.handler.ScopedHandler.nextScope(ScopedHandler.java:203)
	at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:480)
	at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:1667)
	at org.eclipse.jetty.server.handler.ScopedHandler.nextScope(ScopedHandler.java:201)
	at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:1247)
	at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:144)
	at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:132)
	at org.eclipse.jetty.server.Server.handle(Server.java:505)
	at org.eclipse.jetty.server.HttpChannel.handle(HttpChannel.java:370)
	at org.eclipse.jetty.server.HttpConnection.onFillable(HttpConnection.java:267)
	at org.eclipse.jetty.io.AbstractConnection$ReadCallback.succeeded(AbstractConnection.java:305)
	at org.eclipse.jetty.io.FillInterest.fillable(FillInterest.java:103)
	at org.eclipse.jetty.io.ChannelEndPoint$2.run(ChannelEndPoint.java:117)
	at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.runTask(EatWhatYouKill.java:333)
	at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.doProduce(EatWhatYouKill.java:310)
	at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.tryProduce(EatWhatYouKill.java:168)
	at org.eclipse.jetty.util.thread.strategy.EatWhatYouKill.run(EatWhatYouKill.java:126)
	at org.eclipse.jetty.util.thread.ReservedThreadExecutor$ReservedThread.run(ReservedThreadExecutor.java:366)
	at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:698)
	at org.eclipse.jetty.util.thread.QueuedThreadPool$Runner.run(QueuedThreadPool.java:804)
	at java.lang.Thread.run(Thread.java:748)