We released updates for our apps recently and they've been announced several times through our apps and website in the past weeks, but it seems that some didn't get the notices.
It is important to use the latest apps or the latest server profiles if you use OpenVPN XOR, AES-128 and AES-256 connection types, or else connections won't be possible starting today, January 03, 2024.
Please check the announcement and make the necessary updates: Important OpenVPN / Apps update (mirror)