UltimMC hangs before process completes via task manager when trying to install modpack

[Niotferdi]

Operating System

Windows

Description of bug

Can't import mod pack

Steps to reproduce

Import zip archive with mod pack (in my case Rebirth+of+the+Night-3.1.1a.zip), confirm creation of a new instance
After that, the program will stop responding to any user actions. Closing it through the task manager will not import a set of mods

Suspected cause

UltimMC-0.log:
https://pastebin.com/ts4Yx1Ty

This issue is unique

• I have searched the issue tracker and did not find an issue describing my bug.

[Ka1dz0]

You have to wait longer, it took me 5-10 minutes

[Niotferdi]

I waited and UltimMC gave this error:

Archive does not contain a recognized modpack type.

[Ka1dz0]

Well, it's been like that for over two months now.
Curseforge banned modpack uploads by third-party clients. (only some can).
Use either an official client or PolyMC to download the modpack, then when you create a modpack do the import (in PolyMC)
and upload the imported archive to UltimMC