Can't update from 1.14.4 please help

I started a server on 1.14.4 last year and I haven't been able to update it to any of the newer versions of minecraft.

It's running on PaperMC

When I try to update to a newer version, either it doesn't let me on (when updating to 1.15) or it resets EVERYTHING (when updating to 1.16.1)

If anyone is willing to help, please let me know if you need any additional information. Thank you.

Quote from Bluewy

What happens when you try updating to 1.15?

It won't let me on. I can give you screenshots if you want.

Quote from Bluewy

yes pelase.

Okay here's the log, console, and the message when I try to get on the server.

Link to log:

It works completely fine on 1.14.4 by the way. But when I update it to 1.15 I can't even get on it.

Quote from Roman

You're using Tlauncher?

Not sure what that is.

Edit: I looked it up and I'm not using Tlauncher, other servers work fine for me and my aternos server worked flawlessly on 1.14.4

[Server thread/WARN]: Can't keep up! Is the server overloaded? Running 5618ms or 112 ticks behind

Does this mean I have too many plugins? It worked fine on 1.14.4 but maybe by updating to 1.15 it was just too much?

Quote from Roman

Update again to 1.15 and share the server log using the share button on the log page

I deleted the plugin "Ultimate Claims" but I'm still unable to connect to the server.

I just deleted a bunch of other plugins and it's working.