This score is unavailable and other account issues

Dear MuseScore,

For the past few days, there appears to have been a number of issues with my account, my groups and my scores.

Last Wednesday I posted in this forum that I was unable to move four scores to my DandDmvc group. The next day, this appeared to resolve itself. However, today I've had an experienced choir member (UN: Robinwintour) tell me that the scores I posted are still unavailable to him, saying "This score is unavailable"

Also, over this weekend I had a new choir member create a MuseScore account. He created the account, and I invited him to join the MonMVC group. But, by the time he had received the email, his login details were no longer recognised. I told him to leave it a day, and then create the account again with the same email/username details (UN: HywelWilliams). He did this today, and I sent him a new invite. And he was then able to access the MonMVC group discussion, and the sheet music list. But when he clicked on a score title, he was presented with "This score is unavailable".

In summary, two members of two different groups appear to not be able to access scores that I can see from my account are uploaded and in the groups. I've made no changes to my system, and upload scores directly from the 871c8ce application, and access the site currently using Chrome Version 64.0.3282.167 (Official Build) (64-bit). I'm really perplexed as to what is going on. Any help gratefully received.

Kind regards,
Pete Alan