I reinstalled my PI, moving from Jessie to Stretch. I also reinstalled PiVPN, following the documented procedure, added a user, copied the OVPN file to my Android mobile, and tried to connect. This failed. In the log of the VPN server, the following lines were added multiple times:
Dec 16 16:42:13 raspberrypi ovpn-server: Authenticate/Decrypt packet error: packet HMAC authentication failed
Dec 16 16:42:13 raspberrypi ovpn-server: TLS Error: incoming packet authentication failed from [AF_INET]<My external IP address>:44192
It worked perfectly on Jessie, and I don't know what I'm doing wrong this time.
On Android, I have OpenVPN Connect version 3.0.5
On Raspbian, I have the following
PRETTY_NAME="Raspbian GNU/Linux 9 (stretch)"
OpenVPN 2.4.0 arm-unknown-linux-gnueabihf [SSL (OpenSSL)] [LZO] [LZ4] [EPOLL] [PKCS11] [MH/PKTINFO] [AEAD] built on Jul 18 2017
library versions: OpenSSL 1.0.2l 25 May 2017, LZO 2.08
Does anybody have an idea what can cause this error?