Generate NFTs with this simple code NOT generating Metadata file

Having followed the Generate NFTs with this simple code (this could make you millions) PART 1 tutorial, I am coming up with the following strange issues.

Running node index.js correctly generates the 10 unique mutants which I can find in the output folder, however, it doesn’t generate any of their corresponding metadata files at all.

Also I noticed that after the:

#########################################
Welcome to Rekt City - Meet the Survivors
#########################################

I get the following error messages… where am I going wrong?

TypeError [ERR_INVALID_ARG_TYPE]: The “url” argument must be of type string. Received undefined
at validateString (internal/validators.js:124:11)
at Url.parse (url.js:170:3)
at Object.urlParse [as parse] (url.js:157:13)
at dispatchHttpRequest (/home/sirbt/Desktop/Bootstrap/NFTGenerator/moralis-mutants-nft-engine-main/node_modules/axios/lib/adapters/http.js:118:22)
at new Promise ()
at httpAdapter (/home/sirbt/Desktop/Bootstrap/NFTGenerator/moralis-mutants-nft-engine-main/node_modules/axios/lib/adapters/http.js:48:10)
at dispatchRequest (/home/sirbt/Desktop/Bootstrap/NFTGenerator/moralis-mutants-nft-engine-main/node_modules/axios/lib/core/dispatchRequest.js:58:10)
at Axios.request (/home/sirbt/Desktop/Bootstrap/NFTGenerator/moralis-mutants-nft-engine-main/node_modules/axios/lib/core/Axios.js:108:15)
at Axios. [as post] (/home/sirbt/Desktop/Bootstrap/NFTGenerator/moralis-mutants-nft-engine-main/node_modules/axios/lib/core/Axios.js:140:17)
at Function.wrap [as post] (/home/sirbt/Desktop/Bootstrap/NFTGenerator/moralis-mutants-nft-engine-main/node_modules/axios/lib/helpers/bind.js:9:15)
at /home/sirbt/Desktop/Bootstrap/NFTGenerator/moralis-mutants-nft-engine-main/src/metadata.js:147:8 {
code: ‘ERR_INVALID_ARG_TYPE’
}

A little help here please!

I have been patiently waiting!