D365FO - Ошибка 500 There is a problem with the server после установки PU24 на 7.2 PU20

[MarinaAX]

1. IIS логи - пустые.
2. Сертификаты - годные. Повторное развёртывание сертификатов не помогло.
3. Т.к. ошибка 500 - общая, то вот подробности из Application лога:
   Warning 5/9/2019 11:23:34 PM ASP.NET 4.0.30319.0 Event ID: 1310 Web Event
   
   Event code: 3007
   Event message: A compilation error has occurred.
   Event time: 5/9/2019 11:23:34 PM
   Event time (UTC): 5/9/2019 11:23:34 PM
   Event ID: bfd742354c8441f881bcbd69e5ce2878
   Event sequence: 3
   Event occurrence: 1
   Event detail code: 0
   
   Application information:
   Application domain: /LM/W3SVC/2/ROOT-74-132019178132609156
   Trust level: Full
   Application Virtual Path: /
   Application Path: K:\AosService\WebRoot\
   Machine name: AX3
   
   Process information:
   Process ID: 1852
   Process name: w3wp.exe
   Account name: NT AUTHORITY\NETWORK SERVICE
   
   Exception information:
   Exception type: HttpCompileException
   Exception message: k:\AosService\WebRoot\App_Code\Global.asax.cs(30): error CS0234: The type or namespace name 'Extensions' does not exist in the namespace 'Microsoft' (are you missing an assembly reference?)
   at System.Web.Compilation.AssemblyBuilder.Compile()
   at System.Web.Compilation.BuildProvidersCompiler.PerformBuild()
   at System.Web.Compilation.CodeDirectoryCompiler.GetCodeDirectoryAssembly(VirtualPath virtualDir, CodeDirectoryType dirType, String assemblyName, StringSet excludedSubdirectories, Boolean isDirectoryAllowed)
   at System.Web.Compilation.BuildManager.CompileCodeDirectory(VirtualPath virtualDir, CodeDirectoryType dirType, String assemblyName, StringSet excludedSubdirectories)
   at System.Web.Compilation.BuildManager.CompileCodeDirectories()
   at System.Web.Compilation.BuildManager.EnsureTopLevelFilesCompiled()
   at System.Web.Compilation.BuildManager.CallAppInitializeMethod()
   at System.Web.Hosting.HostingEnvironment.Initialize(ApplicationManager appManager, IApplicationHost appHost, IConfigMapPathFactory configMapPathFactory, HostingEnvironmentParameters hostingParameters, PolicyLevel policyLevel, Exception appDomainCreationException)
   
   
   
   Request information:
   Request URL: https://ax3-url.cloudax.dynamics.com:443/
   Request path: /
   User host address: 127.0.0.1
   User:
   Is authenticated: False
   Authentication Type:
   Thread account name: NT AUTHORITY\NETWORK SERVICE
   
   Thread information:
   Thread ID: 6
   Thread account name: NT AUTHORITY\NETWORK SERVICE
   Is impersonating: False
   Stack trace: at System.Web.Compilation.AssemblyBuilder.Compile()
   at System.Web.Compilation.BuildProvidersCompiler.PerformBuild()
   at System.Web.Compilation.CodeDirectoryCompiler.GetCodeDirectoryAssembly(VirtualPath virtualDir, CodeDirectoryType dirType, String assemblyName, StringSet excludedSubdirectories, Boolean isDirectoryAllowed)
   at System.Web.Compilation.BuildManager.CompileCodeDirectory(VirtualPath virtualDir, CodeDirectoryType dirType, String assemblyName, StringSet excludedSubdirectories)
   at System.Web.Compilation.BuildManager.CompileCodeDirectories()
   at System.Web.Compilation.BuildManager.EnsureTopLevelFilesCompiled()
   at System.Web.Compilation.BuildManager.CallAppInitializeMethod()
   at System.Web.Hosting.HostingEnvironment.Initialize(ApplicationManager appManager, IApplicationHost appHost, IConfigMapPathFactory configMapPathFactory, HostingEnvironmentParameters hostingParameters, PolicyLevel policyLevel, Exception appDomainCreationException)
   Custom event details:

Заранее, большое спасибо за помощь!