I've met a very strange problem. URL such as http://wei-.x.yupoo.com
can be opened with Windows PC, macOS, iOS browser, but not with Android browser, it reports DNS error.
Can any one help me to figure out why? I've checked RFC7320 and RFC3986, in RFC3986 sec 3.1
Scheme names consist of a sequence of characters beginning with a
letter and followed by any combination of letters, digits, plus
("+"), period ("."), or hyphen ("-"). Although schemes are case-
insensitive, the canonical form is lowercase and documents that
specify schemes must do so with lowercase letters. An implementation should accept uppercase letters as equivalent to lowercase in scheme
names (e.g., allow "HTTP" as well as "http") for the sake of
robustness but should only produce lowercase scheme names for
consistency.
Seems this url should be fine.