Can't sync with the web app (Nextcloud third-party server)

[mewsmagic]

This is the error that shows up when I try to sync the web app on iPhone.

These are my configurations on both web app and desktop app. On desktop app it works perfectly, while on web it simply does not work, it shows the error above.

I've seen in other articles that it may be an issue with the web app not being whitelisted on Nextcloud's webapppassword app, however, I'm not on nextcloud's own server, I use another due to the bigger cloud space on the free plan. Thus, I cannot log in on nextcloud app store and neither install these apps. I'm not the admin for my server, idk if I made a mistake with my nextcloud account, but for some reason I'm not and my functions are much more limited unfortunately.

This may totally be a noob question and I'm so sorry for that, I don't understand code at all, so even the available resources on this issue have been difficult for me to figure out. Perhaps I can install the nextcloud apps and I just don't know how. But this logging issue has been a headache, syncing between devices is important to me and this app is so amazing, I really wanna be able to use despite this difficulty.

Thanks in advance!