Having read something similiar on reddits r/torrent, someone said that (this case applies to µTorrent) as long as your router is not compatible with UPnP/NAT but you still manually opened the ports on the router, you can disable that function. In that particular case, µTorrent was blocking itself from downloading torrents just because the feature "Forward port with UPnP/NAT" was enabled, but the router did not support UPnP/NAT, thus the user had the port forwarded manually. Disabling that feature, µTorrent got to download the torrents without any problems.
In short (and applied on Tixati): If your router does *not* support UPnP/NAT, you can disable that feature in Tixati, as long as you have the port used by Tixati forwarded in the router's settings.
For me, it's like...
[12:33:16] listening on tcp:0.0.0.0:15846
[12:33:16] listening on udp:0.0.0.0:15846
[12:33:16] listening on tcp:[::]:15846
[12:33:16] listening on udp:[::]:15846
...without any other things happening around it.
canyouseeme.org can see my port indeed:
Success: I can see your service on 88.72.*.* on port (15846)
Your ISP is not blocking port 15846
Sorry for any mistakes, I'm a little drunk. :-)