Http tenant resolvers should be fault tolerant.

src/Volo.Abp.AspNetCore.MultiTenancy/Volo/Abp/AspNetCore/MultiTenancy/CookieTenantResolver.cs

@@ -7,7 +7,7 @@ namespace Volo.Abp.AspNetCore.MultiTenancy
     {
         protected override string GetTenantIdOrNameFromHttpContextOrNull(ITenantResolveContext context, HttpContext httpContext)
         {
-            return httpContext.Request.Cookies[context.GetAspNetCoreMultiTenancyOptions().TenantIdKey];
+            return httpContext.Request?.Cookies[context.GetAspNetCoreMultiTenancyOptions().TenantIdKey];
         }
     }
 }

src/Volo.Abp.AspNetCore.MultiTenancy/Volo/Abp/AspNetCore/MultiTenancy/DomainTenantResolver.cs

@@ -16,6 +16,11 @@ namespace Volo.Abp.AspNetCore.MultiTenancy
 
         protected override string GetTenantIdOrNameFromHttpContextOrNull(ITenantResolveContext context, HttpContext httpContext)
         {
+            if (httpContext.Request?.Host == null)
+            {
+                return null;
+            }
+
             var hostName = httpContext.Request.Host.Host.RemovePreFix("http://", "https://");
             var extractResult = FormattedStringValueExtracter.Extract(hostName, _domainFormat, true);
 

src/Volo.Abp.AspNetCore.MultiTenancy/Volo/Abp/AspNetCore/MultiTenancy/HeaderTenantResolver.cs

@@ -11,7 +11,7 @@ namespace Volo.Abp.AspNetCore.MultiTenancy
     {
         protected override string GetTenantIdOrNameFromHttpContextOrNull(ITenantResolveContext context, HttpContext httpContext)
         {
-            if (httpContext.Request.Headers.IsNullOrEmpty())
+            if (httpContext.Request == null || httpContext.Request.Headers.IsNullOrEmpty())
             {
                 return null;
             }

src/Volo.Abp.AspNetCore.MultiTenancy/Volo/Abp/AspNetCore/MultiTenancy/HttpTenantResolverBase.cs

@@ -1,4 +1,7 @@
+using System;
+using JetBrains.Annotations;
 using Microsoft.AspNetCore.Http;
+using Microsoft.Extensions.Logging;
 using Volo.Abp.MultiTenancy;
 using Volo.ExtensionMethods;
 
@@ -6,6 +9,13 @@ namespace Volo.Abp.AspNetCore.MultiTenancy
 {
     public abstract class HttpTenantResolverBase : ITenantResolver
     {
+        private readonly ILogger<HttpTenantResolverBase> _logger;
+
+        protected HttpTenantResolverBase(ILogger<HttpTenantResolverBase> logger)
+        {
+            _logger = logger;
+        }
+
         public virtual void Resolve(ITenantResolveContext context)
         {
             var httpContext = context.GetHttpContext();
@@ -14,7 +24,14 @@ namespace Volo.Abp.AspNetCore.MultiTenancy
                 return;
             }
 
-            ResolveFromHttpContext(context, httpContext);
+            try
+            {
+                ResolveFromHttpContext(context, httpContext);
+            }
+            catch (Exception e)
+            {
+                _logger.LogWarning(e.ToString());
+            }
         }
 
         private void ResolveFromHttpContext(ITenantResolveContext context, HttpContext httpContext)
@@ -26,6 +43,6 @@ namespace Volo.Abp.AspNetCore.MultiTenancy
             }
         }
 
-        protected abstract string GetTenantIdOrNameFromHttpContextOrNull(ITenantResolveContext context,HttpContext httpContext);
+        protected abstract string GetTenantIdOrNameFromHttpContextOrNull([NotNull] ITenantResolveContext context, [NotNull] HttpContext httpContext);
     }
 }

src/Volo.Abp.AspNetCore.MultiTenancy/Volo/Abp/AspNetCore/MultiTenancy/QueryStringTenantResolver.cs

@@ -7,7 +7,7 @@ namespace Volo.Abp.AspNetCore.MultiTenancy
     {
         protected override string GetTenantIdOrNameFromHttpContextOrNull(ITenantResolveContext context, HttpContext httpContext)
         {
-            if (!httpContext.Request.QueryString.HasValue)
+            if (httpContext.Request == null || !httpContext.Request.QueryString.HasValue)
             {
                 return null;
             }