Can't import a chessbase annotated PGN file to lichess study.

How long the annotation is shouldn't limit the addition to a study if that's the problem.

Chessbase link: en.chessbase.com/post/bobby-fischer-in-iceland-45-years-ago-6

Please scroll to the game that Fischer won against Spassky (starts with 1. c4 by Fischer)

Pastebin link: pastebin.com/pB0rHjw3

That's probably because of the null move, i.e. -- in
42. Qxh6 {leaves Black no recourse against} -- 43. Rg6+

You can replace it with an actual move or move it inside a comment, i.e. 42. Qxh6 {leaves Black no recourse against -- 43. Rg6+}