2876452 - How to solve the exception: Invalid locale format in SAP Commerce Cloud

java.lang.IllegalArgumentException: Invalid locale format: z1 at org.apache.commons.lang.LocaleUtils.toLocale(LocaleUtils.java:104) at de.hybris.platform.commercefacades.storesession.converters.populator.LanguagePopulator.toLocale(LanguagePopulator.java:39) at de.hybris.platform.commercefacades.storesession.converters.populator.LanguagePopulator.populate(LanguagePopulator.java:34) at de.hybris.platform.commercefacades.storesession.converters.populator.LanguagePopulator.populate(LanguagePopulator.java:1) at de.hybris.platform.converters.impl.AbstractPopulatingConverter.populate(AbstractPopulatingConverter.java:73) at de.hybris.platform.converters.impl.AbstractConverter.convert(AbstractConverter.java:41) at de.hybris.platform.converters.Converters.convertAll(Converters.java:64) at de.hybris.platform.commercefacades.storesession.impl.DefaultStoreSessionFacade.getAllLanguages(DefaultStoreSessionFacade.java:234) at de.hybris.platform.cmsfacades.users.services.impl.DefaultCMSUserService.getAllSupportedLanguages(DefaultCMSUserService.java:103) at de.hybris.platform.cmsfacades.users.services.impl.DefaultCMSUserService.getLanguagesForUser(DefaultCMSUserService.java:84) at de.hybris.platform.cmsfacades.users.services.impl.DefaultCMSUserService.getReadableLanguagesForUser(DefaultCMSUserService.java:51) at de.hybris.platform.cmsfacades.users.services.impl.DefaultCMSUserService.getReadableLanguagesForCurrentUser(DefaultCMSUserService.java:45) at de.hybris.platform.cmsfacades.common.populator.impl.DefaultLocalizedPopulator.populate(DefaultLocalizedPopulator.java:40) at de.hybris.platform.cmsfacades.sites.populator.model.SiteModelPopulator.populate(SiteModelPopulator.java:47) at de.hybris.platform.cmsfacades.sites.populator.model.SiteModelPopulator.populate(SiteModelPopulator.java:1) at de.hybris.platform.converters.impl.AbstractPopulatingConverter.populate(AbstractPopulatingConverter.java:73) at de.hybris.platform.converters.impl.AbstractConverter.convert(AbstractConverter.java:41) at de.hybris.platform.cmsfacades.sites.impl.DefaultSiteFacade.lambda$3(DefaultSiteFacade.java:79) at java.util.stream.ReferencePipeline$3$1.accept(ReferencePipeline.java:193) at java.util.HashMap$KeySpliterator.forEachRemaining(HashMap.java:1556) at java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:482) at java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:472) at java.util.stream.ReduceOps$ReduceOp.evaluateSequential(ReduceOps.java:708) at java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234) at java.util.stream.ReferencePipeline.collect(ReferencePipeline.java:499) at de.hybris.platform.cmsfacades.sites.impl.DefaultSiteFacade.getAllSiteData(DefaultSiteFacade.java:80) at de.hybris.platform.cmswebservices.sites.controller.SiteController.getAllSites(SiteController.java:58) at de.hybris.platform.cmswebservices.sites.controller.SiteController$$FastClassBySpringCGLIB$$3093f173.invoke(<generated>) at org.springframework.cglib.proxy.MethodProxy.invoke(MethodProxy.java:204) at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.invokeJoinpoint(CglibAopProxy.java:736) at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:157) at org.springframework.security.access.intercept.aopalliance.MethodSecurityInterceptor.invoke(MethodSecurityInterceptor.java:69) at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:179) at org.springframework.aop.framework.CglibAopProxy$DynamicAdvisedInterceptor.intercept(CglibAopProxy.java:671) at de.hybris.platform.cmswebservices.sites.controller.SiteController$$EnhancerBySpringCGLIB$$cd9e90ed.getAllSites(<generated>) at sun.reflect.GeneratedMethodAccessor719.invoke(Unknown Source) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:498) at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:205)