I've noticed something about openVPN and PIA and a question about SHA

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when I set it to AES256CBC right off the bat it doesn't work
However if I set it to BF128CBC, asve, then AES128CBC, save, then AES256CBC save it works. I use port UDP 9201.
Anyone know how to change SHA1(160 bit) to SHA256? And how do I modify the handshake to RSA-4096?
Thanks