try

src/HeartTrackAPI/Utils/AppBootstrap.cs

@@ -172,6 +172,7 @@ public class AppBootstrap(IConfiguration configuration)
 
     public void Configure(WebApplication app, IWebHostEnvironment env)
     {
+//        app.UsePathBase("/containers/HeartDev-api");
         app.UseHttpsRedirection();
         app.MapIdentityApi<IdentityUser>();
 
@@ -184,8 +185,28 @@ public class AppBootstrap(IConfiguration configuration)
         if (true)
         {
             var apiVersionDescriptionProvider = app.Services.GetRequiredService<IApiVersionDescriptionProvider>();
-            app.UseSwagger();
+            app.UseSwagger(options =>
-            app.UseSwaggerUI();
+            {
+                options.PreSerializeFilters.Add((swagger, httpReq) =>
+                {
+                    if (httpReq.Headers.ContainsKey("X-Forwarded-Host"))
+                    {
+                        //The httpReq.PathBase and httpReq.Headers["X-Forwarded-Prefix"] is what we need to get the base path.
+                        //For some reason, they returning as null/blank. Perhaps this has something to do with how the proxy is configured which we don't have control.
+                        //For the time being, the base path is manually set here that corresponds to the APIM API Url Prefix.
+                        //In this case we set it to 'sample-app'. 
+
+                        var basePath = "/containers/HeartDev-api";
+                        var serverUrl = $"{httpReq.Scheme}://{httpReq.Headers["X-Forwarded-Host"]}/{basePath}";
+                        swagger.Servers = new List<OpenApiServer> { new OpenApiServer { Url = serverUrl } };
+                    }
+                });
+            });
+            app.UseSwaggerUI(options =>
+                {
+                    options.RoutePrefix = string.Empty;
+                    options.SwaggerEndpoint("swagger/v1/swagger.json", "My Api (v1)");
+                });
             app.MapSwagger();
 /*            app.UseSwaggerUI(options =>
             {