CURL error “URL using bad/illegal format or missing URL” when trying to pass variable as a part of URL

Set IFS=$' \t\r\n' at the top of your script.

IFS is the Interactive Field Separator.

In UNIX, IFS is space, tab, newline, or $' \t\n', but on Windows this needs to be $' \t\r\n'.

The ^M character is \r.