Mongoose: (CastError) Cast to [ObjectId] failed for value - arrays

Question

I'm having a lil problem I've been trying to solve for a while and despite looking online pretty much everywhere I can't find the solution to my problem.
I have 2 mongoose schemas. One "Post" schema and one "Tag" schema.
const postSchema = new Schema({
creator:{type:mongoose.Types.ObjectId, required:true, ref:'User'},
type:{type:String, required:true},
title:{type:String, maxlength:14},
description:{type:String, maxlength:1140},
content:{type:String},
tags:[{type:mongoose.Types.ObjectId, ref:'Tag'}],
date:{type:Date},
});
const tagSchema = new Schema({
name:{type:String, required:true, unique:true},
bgImages:[{type:String}],
posts:[{type:mongoose.Types.ObjectId, ref:'Post'}],
});
When I create a new post, I want to be able to add multiple tags to the tags array in the Post, so what I tried doing is find the ID's of the tags selected by the user and send the array of id's in the POST request.
This is the exact error I get:
'tags.0': CastError: Cast to [ObjectId] failed for value "["60d193ab04caf9336cc9169b,60d193b504caf9336cc9169c"]" (type string) at path "tags.0"
Both the ID's exist in the Tag collection. If I send only one Id in the request it works, but if I send an array of Id's it doesn't.
Something I have in mind is that it sends an array of a single string from what looks like, instead of an array of strings (where each string is the ID).
Can someone help me figure out what's the issue? Thanks a lot.

Answer 1

Found the problem. As I thought it's because I was sending an array containing one single string instead of an array of atomic strings.
Had to split the array with "," to solve the problem.