OMDB API Fails to find any Title starting with a Number

Question

Yeah, the OMDB API is working fine except for any Title that starts with a number. I figured it's just something I don't know about, so thought I'd ask.

Titles like: 3-10 to Yuma, 6 Underground, 1917, 12 Strong, etc. - all return a 401. All apha titles work without a hitch, just numeric-starting titles fail.

I do the requests, locally, with javascript.

Here's a request capture (HTTP Headers Live, FF addon):

https://omdbapi.com/?s=6 Underground&y=2019&page=1&key=********
Host: omdbapi.com
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:109.0) Gecko/20100101 Firefox/118.0
Accept: */*
Accept-Language: en-US,en;q=0.5
Accept-Encoding: gzip, deflate, br
Origin: null
DNT: 1
Connection: keep-alive
Sec-Fetch-Dest: empty
Sec-Fetch-Mode: cors
Sec-Fetch-Site: cross-site
GET: HTTP/2.0 401

So, the request looks ok to me and the same request format sure works with all alpha titles. Do I have to 'escape' leading numeric text somehow? Like I said, just thought I'd ask, 'cause I don't know and DDG didn't show anything relevant.

Thanks for any insight.