Cranberry

I once saw a post about it where they had said they didn't want to maintain it anymore. It got replaced with a 3 part cut scene viewer online that summarizes the events of the extended offline mode. The special item you previously received as a reward for clearing the extended offline mode can now be obtained by watching all 3 cut scenes. After watching the 3rd one, you'll need to log off, and then log in again in order to receive your prize.

Give HyDEKI's suggestion a try. I set up my VPN differently through a cabled connection, I never used the hotspot method.

How are you attempting to connect your Switch to the VPN? Are you using a network cable to a PC or are you trying to connect it to a wireless signal?

You might try using SoftEther and see if you still have the same problem using that service. Make sure you really are connected to the VPN. I needed to have my Switch connect to a PC that was sharing the connection for it to work. Other players had a phone act as a hot spot and had their switch connect to the VPN signal as a hot spot. If you're getting the error your Switch probably is not seeing the VPN.

If you get the full game you can continue where you left off. The trial goes to about the end of V2 from what I've heard. You probably can't actually fight the V2 final boss though.

Yes, you need a 16GB memory stick and a Japanese Wii. You can't simply mod a wii to bypass region protection. It needs to have the Japanese operating system on it. If it is not a Japanese OS, the game won't load even if you bypass region lock. Honestly, are you sure you want to do this? This is going to be a pain to setup and pretty pricey all for a really short offline mode. On other platforms, they summarize the offline mode through a 3 part cut scene viewer showing the important parts of the offline mode. There's also either mine or Nawaria's Youtube coverage of the offline mode that demonstrates it. Otherwise, either you need to buy a Japanese Wii, or find some risky soft mods that can switch your Wii to a Japanese OS (this may cost you all your download Wii games) so that DQX can run and install.

On Switch and PS4, the offline mode was removed before these versions were released. There is no way to access it on these versions. On PC version, if you installed the version 1 disk, technically the offline mode gets installed onto your computer. However when you launch the game, it forces an update and this update removes the offline mode. In theory, if you could bypass the Internet check and prevent it from updating, you could play the offline mode. I'm not aware of anyone that has done this. Presumably it's the same way with WiiU. If you want to play the offline mode, the only way is to use the original Wii version.

The PS4 version has never had the offline mode. It was removed before the PS4 version was released. The Wii version is the only version that can play the offline mode.

Invite sent.

Control T on the keyboard. Alternately you can press the Plus button, tab over to the orange chat log screen and pull up the window that way.

All 3 team invites have been sent.

The game did not allow me to send you an invite. Please make sure your character ID is correct and that you are not already on a different team. Is your name really just い?

Hemi you could not be added to the team. Make sure you are not already on another team. You cannot be on more than 1 team at a time. Proteus you need to provide your character ID. You cannot be added without it.

Invite sent to Akana. Invite sent to リュ. (Your name is actually リユ　not リュ As in not a small ュ) Proteus, choose つよさ from the main menu to see your ID.

Welcome to the game. Feel free to join up with us at any time. No problem to play together. Not really any English guides though. You can use Google Translate on some of the JP guides though. It's not perfect but it usually helps get the idea of what you need to do next.