FK in table is not working while migrate

When I create a migration for table at that time there is an issue with its through following error.

Illuminate\Database\QueryException : SQLSTATE[HY000]: General error: 1005 Can't create table yourwebs_veridocedu.#sql-2c46_8e (errno: 150 "Foreign key constraint is incorrectly formed") (SQL: alter table user_role_mappings add constraint user_role_mappings_user_id_foreign foreign key (user_id) references users (id) on delete cascade)

Migration for userrolemapping table:

public function up()
    {
        Schema::create('user_role_mappings', function (Blueprint $table) {
            $table->increments('id');

            $table->integer('user_id');
            $table->integer('group_id');
            $table->integer('roleid');
            $table->integer('status');
            $table->integer('createdby');
            $table->integer('modifiedby');
            $table->string('publicguid');
            $table->string('privateguid');
            $table->timestamps();

            $table->foreign('user_id')->references('id')->on('users')->onDelete('cascade');
            $table->foreign('group_id')->references('id')->on('groups')->onDelete('cascade');
        });
    }

Migration for Role table :

public function up()
{
    Schema::create('userroles', function (Blueprint $table) {
        $table->increments('id');
        $table->string('rolename');
         $table->integer('status')->default(1);
        $table->integer('createdby')->default(1);
        $table->integer('modifiedby')->default(1);
        $table->string('publicguid');
        $table->string('privateguid');
        $table->timestamps(); 

    });
}

FK in table is not working which migrate.

via Chebli Mohamed