Remote API method won't create records based on received params - ruby-on-rails

Question

I have an api for mass creating records of a model Series. A remote machine sends a POST request to my url, with an array #series passed as a json parameter, like this:
#series = [{:id=>1,name:"test"}, {:id=>2,name:"test2"}]
req = Net::HTTP::Post.new(post_uri, 'Content-Type' => 'application/json')
req.body = {series: #series}.to_json
res = http.request(req)
but I cannot for the life of me get the respective Series to be created. Here is the method that receives the data and is supposed to create one Series for each hash in the #series array:
def api
series = params[:series]
series.each do |s|
name = s[:name]
if !Series.where(name: name).exists?
Series.create(s)
end
end
end
The params are definitely passed through, but no Series are created. When I check my logs there's a 500 error, but since it's remote, I have no way of getting a more specific error.
When I remove the params and just create a generic Series for each hash in the #series array, it works. For example, with the following code, if #series has 3 hashes, 3 Series are created:
def post_product_data
series = params[:series]
series.each do |s|
name = s[:name]
if !Series.where(name: name).exists?
Series.create #GENERIC SERIES NOT BASED ON PARAMS
end
end
end
I thought it might be a permissions issue, so I tried permitting all params. But when I changed the method to this, I got a "undefined method "permit!" error:
def post_product_data
series = params[:series]
series.each do |s|
name = s[:name]
if !Series.where(name: name).exists?
Series.create(s.permit!) #TRIED PERMITTING ALL PARAMS
end
end
end
Anyone have any ideas?
UPDATE
I changed the offending line to this:
Series.create({id: s[:id], name: s[:name]})
and now it works. I have no idea why, since the hashes should have been inserting the exact same thing. But at least it works finally.