I have installed the ABP with mongoDB and it is on my local machine but having this issue when running the .DBMigrator
[10:52:51 INF] Started database migrations... [10:52:51 INF] Migrating schema for host database... Unhandled exception. System.ArgumentNullException: Value cannot be null. (Parameter 'connectionString') at MongoDB.Driver.Core.Misc.Ensure.IsNotNull[T](T value, String paramName)
"ConnectionStrings": { "Default": "mongodb://localhost:27017/HelloWord" },
I guess you didn't change the ConnectionString in DbMigrator project's
appsettings.json