Serious mistake in Settings - Outbound Network Proxy Type
Proxy Type; If I input "HTTP" (no ") for HTTP Proxy, Orbot fails to connect it. If I input "HTTPS", Orbot connect to (tor node IP):443 via proxy, as expected.
Conclusion: Just remove "HTTP". Or, make a radio selection menu, like
() None (O) HTTPS () SOCKS4 (_) SOCKS5