Dont attache file if use notification Telegram (IIS and PHP)

All Hi.
I recently installed kanboard 1.2.15 on windows server 2019 under IIS.

kanboard: 1.2.15
PHP: 7.4.9
PHP SAPI: cgi-fcgi
HTTP Client: socket
 Windows NT 10.0
 db sqlite
version db: 3.31.1

Everything seems to work, except for attaching files.
The situation is as follows, when I attach a file and click save, the download progress is
it reaches 100% and everything freezes. I redraw the screen, and the file is attached.
Deleting an attached file does not have this effect.
Long experiments and reading documentation on Ikonboard, PHP, IIS, and FastCGI did not lead to anything.

Noticed a feature. There are two projects. One uses telegram notification and the other does not. So in the case where notification via Telegram is not used, attaching files works normally. When I enabled notification and the file attachment stopped working in this project. Disabled - everything is OK. Perhaps there is a problem somewhere on the telegram and Kanboard link.

Can someone help me solve this problem? Thank you very much in advance.