when I want to upload a new song to musescore, it takes a long time to load and nothing happens. it remains so. I updated musehub, musescore and it does the same..

You are on musescore.org. This issue relates to the musescore.com website and you need to report it there, as no one here can help. See the following information:

https://musescore.org/en/faq#faq-314712
https://musescore.org/en/faq#faq-20657
https://musescore.org/en/faq#faq-359393
https://musescore.org/en/node/277874
https://musescore.org/en/node/314712