I cannot cancel meetings from my calendar that were automatically transferred from Skype

Hello, hope someone can help me. On my Teams calendar there are a number of recurring meetings that were probably transferred over directly from Skype. It is really annoying because, although I can schedule other meetings during those times, they appear as overlapping and it looks confusing. When I try to cancel either the occurrence or the series, I alwayys get an error message saying to try again later and I cannot get rid of them. Anyone knows how to get around this glitch? Thanks in advance. Francesca