Im having the exact same problem. I would like to use it with my AVM FritzBox 7590 Wireguard server. 

@Marvin_S the solution does unfortunately not help, it describes what we are trying to do. Importing a WireGuard config file but that is being rejected. 

@cpio92 Have you been successful in the meantime?

Many thanks for any hint, Daniel 

I do run into the same issue.

My FritzBox Router is my Wireguard server and importing the config files in Windows and Android clients works just fine but the TP-Link Router won't load or process the file correctly.

I do have multiple DNS-Entries in the file which are not copied over the the Wireguard-Client properly (information is missing nonwithstanding the fact that the TP-Link Router can't process comma-seperated entries anyway). Also one of the DNS-Entries in the config file is "fritz.box" (unsurprisingly) but the input form seems to not be able to accept anything else but IP-Adresses.

I tried deleting all comma-seperated entires leaving just one IPv4-Adress for the DNS-Server (which is my main one) and one AllowedIP entry (0.0.0.0/0 or 192.168.0.0/24). The TP-Router can process that i can enable the VPN-Connection but it does not seem to work since the status keeps hanging on "connecting" and does not move further then that. A wireguard connection can't be established.

There is also no evidence of an error in the log files on the TP-Link router or on the VPN server.

It's a real bummer since i bought that product specifically for that built-in wireguard client but the implementation seems to be wrong here (Again  @Marvin_S : Android and Windows implementations of the Wireguard-Client both work with the config-file out of the box - the error is on your side)

I'm happy to help out with testing and debugging

Further information: I'm running the newest firmware 1.0.20

  @Yravoul 

Thank you so much for your extensive response!!

Yes, I can confirm everything you wrote and tried exactly the same. Stripping the commas, only using one CIDR range, no IPv6, DNS to the FRITZ!Box IP or even 1.1.1.1.

Everything works fine with macOS and iOS WireGuard clients but not on the TPlink.

I have also had no luck with an IPsec tunnel to the FRITZ!Box.

For the time being I helped myself out with an OpenVPN connection to the Synology NAS that's behind the FRITZ!Box but that has a poorer performance and many public WiFi's block the required ports. And originally I wanted to avoid exposing the NAS even if it's OVPN only.

Still need to play around with Cloudflare. Maybe there's an option there. The NAS has an cloudflare tunnel already.

All this leads me to the impression that there's issue with the initial connection to the FRITZ!Box in the first place. No handshake whatsoever.

I've read that folks where successful with gl-inet routers but I am otherwise quite happy with the AX1500 and reluctant to throw more money at the setup which I mainly want for out of country Netflix & co.

  @DanielWi 

Thank you, i tried establishing and IPSec as well with the same disappointing result. Even tried enabling the VPN-Connection from different ISPs (Homenetwork, Backup-Home-Network, Hotspot from my Phone) from a wired connection, from a wireless connection...  

So i second your impression, seems like the TP-Link Router is unable to initialize a handshake with the remote Fritzbox in the first place.

For my planned trip i will install Wireguard Clients on each device individually, as laborious as it is.