apt update问题

art4hydra

问题起因：使用 “sudo apt-get update”和“sudo apt-get upgrade”时出现报错，更换5-20版本的纯净源，part_qt,full_qt版本均会出现关于W: Failed to fetch http://repos.rcn-ee.com/debian/dists/buster/InRelease  Cannot initiate the connection to repos.rcn-ee.com:80 (2600:3c00::f03c:91ff:fe37:6ad5). - connect (101: Network is unreachable) Could not connect to repos.rcn-ee.com:80 (45.33.2.10), connection timed outW: Some index files failed to download. They have been ignored, or old ones used instead.
和
E: Failed to fetch http://117.156.30.133/cache/mirr ... ed519ea3c4117fce67a  Hash Sum mismatch

的报错

有人遇到过这样的问题么