Windows Universal Application Error: The app manifest must be valid as per schema

Severity Code Description Project File Line Suppression State Error Validation error. error C00CE169: App manifest validation error: The app manifest must be valid as per schema: Line 10, Column 57, Reason: 'CN=#Arun' violates pattern constraint of '(CN|L|O|OU|E|C|S|STREET|T|G|I|SN|DC|SERIALNUMBER|Description|PostalCode|POBox|Phone|X21Address|dnQualifier|(OID\.(0|[1-9][0-9]*)(\.(0|[1-9][0-9]*))+))=(([^,+="<>#;])+|".*")(, ((CN|L|O|OU|E|C|S|STREET|T|G|I|SN|DC|SERIALNUMBER|Description|PostalCode|POBox|Phone|X21Address|dnQualifier|(OID\.(0|[1-9][0-9]*)(\.(0|[1-9][0-9]*))+))=(([^,+="<>#;])+|".*")))*'. The attribute 'Publisher' with value 'CN=#Arun' failed to parse.    SecondApp1    C:\Users\#Arun\source\repos\SecondApp1\SecondApp1\bin\x64\Debug\AppxManifest.xml 

What is this error?

<?xml version="1.0" encoding="utf-8"?>
<Package xmlns="http://schemas.microsoft.com/appx/manifest/foundation/windows10" xmlns:mp="http://schemas.microsoft.com/appx/2014/phone/manifest" xmlns:uap="http://schemas.microsoft.com/appx/manifest/uap/windows10" xmlns:genTemplate="http://schemas.microsoft.com/appx/developer/windowsTemplateStudio" IgnorableNamespaces="uap mp genTemplate build" xmlns:build="http://schemas.microsoft.com/developer/appx/2015/build">
  <!--
    THIS PACKAGE MANIFEST FILE IS GENERATED BY THE BUILD PROCESS.

    Changes to this file will be lost when it is regenerated. To correct errors in this file, edit the source .appxmanifest file.

    For more information on package manifest files, see http://go.microsoft.com/fwlink/?LinkID=241727
  -->
  <Identity Name="677DB45F-2894-43D6-AD52-995494564901" Publisher="CN=#Arun" Version="1.0.0.0" ProcessorArchitecture="x64" />
  <mp:PhoneIdentity PhoneProductId="677DB45F-2894-43D6-AD52-995494564901" PhonePublisherId="00000000-0000-0000-0000-000000000000" />
  <Properties>
    <DisplayName>SecondApp1</DisplayName>
    <PublisherDisplayName>#Arun</PublisherDisplayName>
    <Logo>Assets\StoreLogo.png</Logo>
  </Properties>
  <Dependencies>
    <TargetDeviceFamily Name="Windows.Universal" MinVersion="10.0.17134.0" MaxVersionTested="10.0.17763.0" />
    <PackageDependency Name="Microsoft.UI.Xaml.2.0" MinVersion="2.1810.18003.0" Publisher="CN=Microsoft Corporation, O=Microsoft Corporation, L=Redmond, S=Washington, C=US" />
    <PackageDependency Name="Microsoft.NET.CoreRuntime.2.1" MinVersion="2.1.26124.5" Publisher="CN=Microsoft Corporation, O=Microsoft Corporation, L=Redmond, S=Washington, C=US" />
    <PackageDependency Name="Microsoft.VCLibs.140.00.Debug" MinVersion="14.0.27023.1" Publisher="CN=Microsoft Corporation, O=Microsoft Corporation, L=Redmond, S=Washington, C=US" />
  </Dependencies>
  <Resources>
    <Resource Language="EN-US" />
  </Resources>
  <Applications>
    <Application Id="App" Executable="SecondApp1.exe" EntryPoint="SecondApp1.App">
      <uap:VisualElements DisplayName="ms-resource:AppDisplayName" Square150x150Logo="Assets\Square150x150Logo.png" Square44x44Logo="Assets\Square44x44Logo.png" Description="ms-resource:AppDescription" BackgroundColor="transparent">
        <uap:DefaultTile Wide310x150Logo="Assets\Wide310x150Logo.png"></uap:DefaultTile>
        <uap:SplashScreen Image="Assets\SplashScreen.png" />
      </uap:VisualElements>
    </Application>
  </Applications>
  <Capabilities>
    <Capability Name="internetClient" />
    <uap:Capability Name="enterpriseAuthentication" />
  </Capabilities>
  <genTemplate:Metadata>
    <genTemplate:Item Name="generator" Value="Windows Template Studio" />
    <genTemplate:Item Name="wizardVersion" Version="v3.0.19031.2" />
    <genTemplate:Item Name="templatesVersion" Version="v3.0.19031.2" />
    <genTemplate:Item Name="projectType" Value="SplitView" />
    <genTemplate:Item Name="framework" Value="MVVMBasic" />
    <genTemplate:Item Name="platform" Value="Uwp" />
  </genTemplate:Metadata>
  <Extensions>
    <Extension Category="windows.activatableClass.inProcessServer">
      <InProcessServer>
        <Path>WatsonRegistrationUtility.dll</Path>
        <ActivatableClass ActivatableClassId="WatsonRegistrationUtility.WatsonRegistrationManager" ThreadingModel="both" />
      </InProcessServer>
    </Extension>
    <Extension Category="windows.activatableClass.inProcessServer">
      <InProcessServer>
        <Path>CLRHost.dll</Path>
        <ActivatableClass ActivatableClassId="Microsoft.UI.Xaml.Markup.ReflectionXamlMetadataProvider" ThreadingModel="both" />
      </InProcessServer>
    </Extension>
  </Extensions>
  <build:Metadata>
    <build:Item Name="TargetFrameworkMoniker" Value=".NETCore,Version=v5.0" />
    <build:Item Name="VisualStudio" Version="15.0" />
    <build:Item Name="VisualStudioEdition" Value="Microsoft Visual Studio Community 2017" />
    <build:Item Name="OperatingSystem" Version="10.0.16299.15 (WinBuild.160101.0800)" />
    <build:Item Name="Microsoft.Build.AppxPackage.dll" Version="15.0.28307.104" />
    <build:Item Name="ProjectGUID" Value="{05296F3B-818F-42DD-AE38-54E642F57CAC}" />
    <build:Item Name="OptimizingToolset" Value="None" />
    <build:Item Name="TargetRuntime" Value="Managed" />
    <build:Item Name="Microsoft.Windows.UI.Xaml.Build.Tasks.dll" Version="10.0.17763.132" />
    <build:Item Name="UseDotNetNativeSharedAssemblyFrameworkPackage" Value="true" />
    <build:Item Name="MakePri.exe" Version="10.0.17763.132 (WinBuild.160101.0800)" />
  </build:Metadata>
</Package>