VPN: Cannot SSH to any machine (keep stuck)

Problem:
Connected to my VPN server (Unifi Ubiquiti) and can't ssh to any host. (Using Hotspot from cellphone)

ssh -vvv [IP_ADDRESS]
debug1: kex: client->server cipher: aes256-gcm@openssh.com MAC: compression: none
debug1: kex: curve25519-sha256 need=32 dh_need=32
debug1: kex: curve25519-sha256 need=32 dh_need=32
debug3: send packet: type 30
debug1: expecting SSH2_MSG_KEX_ECDH_REPLY (stuck here)

$ cat /etc/fedora-release
Fedora release 31 (Thirty One)

Workaround:
$ sudo ip li set mtu 1200 dev ppp0

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