aspnetboilerplate: Migrations don't work anymore (2.3.0, Oracle)

Apologies that I am not (can not) use the latest version of Abp, and that I am using Oracle which you don’t usually support, but I could use some direction as to where the problem might be.

I have made a simple migration, which works completely fine through the Package-Manager-Console, but when trying to migration on Application startup, it fails, citing that it already has made a connection and can’t make another:

Connection is already part of a local or a distributed transaction

Oracle.ManagedDataAccess.Client.OracleConnection.BeginTransaction(IsolationLevel isolationLevel) +378 Oracle.ManagedDataAccess.Client.OracleConnection.BeginDbTransaction(IsolationLevel isolationLevel) +130 System.Data.Common.DbConnection.BeginTransaction(IsolationLevel isolationLevel) +10 System.Data.Entity.Infrastructure.Interception.DbConnectionDispatcher.<BeginTransaction>b__0(DbConnection t, BeginTransactionInterceptionContext c) +9 System.Data.Entity.Infrastructure.Interception.InternalDispatcher1.Dispatch(TTarget target, Func3 operation, TInterceptionContext interceptionContext, Action3 executing, Action3 executed) +576 System.Data.Entity.Infrastructure.Interception.DbConnectionDispatcher.BeginTransaction(DbConnection connection, BeginTransactionInterceptionContext interceptionContext) +341 System.Data.Entity.Migrations.DbMigrator.ExecuteStatementsWithinNewTransaction(IEnumerable1 migrationStatements, DbConnection connection, DbInterceptionContext interceptionContext) +138 System.Data.Entity.Migrations.DbMigrator.ExecuteStatementsInternal(IEnumerable1 migrationStatements, DbConnection connection, DbInterceptionContext interceptionContext) +346 System.Data.Entity.Migrations.DbMigrator.ExecuteStatementsInternal(IEnumerable1 migrationStatements, DbConnection connection) +509 System.Data.Entity.Migrations.<>c__DisplayClass30.<ExecuteStatements>b__2e() +19 System.Data.Entity.Infrastructure.DefaultExecutionStrategy.Execute(Action operation) +9 System.Data.Entity.Migrations.DbMigrator.ExecuteStatements(IEnumerable1 migrationStatements, DbTransaction existingTransaction) +194 System.Data.Entity.Migrations.DbMigrator.ExecuteStatements(IEnumerable1 migrationStatements) +7 System.Data.Entity.Migrations.DbMigrator.ExecuteOperations(String migrationId, VersionedModel targetModel, IEnumerable1 operations, IEnumerable1 systemOperations, Boolean downgrading, Boolean auto) +828 System.Data.Entity.Migrations.DbMigrator.ApplyMigration(DbMigration migration, DbMigration lastMigration) +364 System.Data.Entity.Migrations.DbMigrator.Upgrade(IEnumerable1 pendingMigrations, String targetMigrationId, String lastMigrationId) +133 System.Data.Entity.Migrations.DbMigrator.UpdateInternal(String targetMigration) +446 System.Data.Entity.Migrations.<>c__DisplayClassc.<Update>b__b() +13 System.Data.Entity.Migrations.DbMigrator.EnsureDatabaseExists(Action mustSucceedToKeepDatabase) +422 System.Data.Entity.Migrations.DbMigrator.Update(String targetMigration) +78 System.Data.Entity.MigrateDatabaseToLatestVersion2.InitializeDatabase(TContext context) +108 System.Data.Entity.Internal.<>c__DisplayClassf1.<CreateInitializationAction>b__e() +76 System.Data.Entity.Internal.InternalContext.PerformInitializationAction(Action action) +60 System.Data.Entity.Internal.InternalContext.PerformDatabaseInitialization() +357 System.Data.Entity.Internal.LazyInternalContext.<InitializeDatabase>b__4(InternalContext c) +7 System.Data.Entity.Internal.RetryAction1.PerformAction(TInput input) +110 System.Data.Entity.Internal.LazyInternalContext.InitializeDatabaseAction(Action1 action) +198 System.Data.Entity.Internal.LazyInternalContext.InitializeDatabase() +73 System.Data.Entity.Internal.InternalContext.ForceOSpaceLoadingForKnownEntityTypes() +60 System.Data.Entity.DbContext.System.Data.Entity.Infrastructure.IObjectContextAdapter.get_ObjectContext() +25 Abp.EntityFramework.AbpDbContext.RegisterToChanges() +27 Abp.Zero.EntityFramework.AbpZeroDbContext3…ctor(String nameOrConnectionString) +29 Project.EntityFramework.ProjectDbContext…ctor(String nameOrConnectionString) in C:\User\Project.EntityFramework\EntityFramework\ProjectAbpContext.cs:176 `

I am really quite stuck. Do you know why there might already be another connection at this point?