當我嘗試使用 apt update 進行更新時，出現以下錯誤。
Err:10 http://ppa.launchpad.net/danielrichter2007/grub-customizer/ubuntu bionic InRelease
Could not connect to ppa.launchpad.net:80 (91.189.95.83), connection timed out Could not connect to ppa.launchpad.net:80 (2001:67c:1560:8008::15), connection timed out
Err:11 http://ppa.launchpad.net/js-reynaud/kicad-5.1/ubuntu bionic InRelease
Unable to connect to ppa.launchpad.net:http:
Err:12 http://ppa.launchpad.net/tista/plata-theme/ubuntu bionic InRelease
Unable to connect to ppa.launchpad.net:http:
Err:13 http://ppa.launchpad.net/ubuntubudgie/backports/ubuntu bionic InRelease
Unable to connect to ppa.launchpad.net:http:
Err:14 http://ppa.launchpad.net/zeal-developers/ppa/ubuntu bionic InRelease
Unable to connect to ppa.launchpad.net:http:
Fetched 7,502 B in 31s (238 B/s)
Reading package lists...
Building dependency tree...
Reading state information...
1 package can be upgraded. Run 'apt list --upgradable' to see it.
W: Failed to fetch http://ppa.launchpad.net/danielrichter2007/grub-customizer/ubuntu/dists/bionic/InRelease Could not connect to ppa.launchpad.net:80 (91.189.95.83), connection timed out Could not connect to ppa.launchpad.net:80 (2001:67c:1560:8008::15), connection timed out
W: Failed to fetch http://ppa.launchpad.net/js-reynaud/kicad-5.1/ubuntu/dists/bionic/InRelease Unable to connect to ppa.launchpad.net:http:
W: Failed to fetch http://ppa.launchpad.net/tista/plata-theme/ubuntu/dists/bionic/InRelease
Unable to connect to ppa.launchpad.net:http:
W: Failed to fetch http://ppa.launchpad.net/ubuntubudgie/backports/ubuntu/dists/bionic/InRelease Unable to connect to ppa.launchpad.net:http:
W: Failed to fetch http://ppa.launchpad.net/zeal-developers/ppa/ubuntu/dists/bionic/InRelease Unable to connect to ppa.launchpad.net:http:
W: Some index files failed to download. They have been ignored, or old ones used instead.
問題是我可以從我的網頁瀏覽器訪問這些鏈接，所以這一定不是伺服器的問題。
我嘗試僅在更新時強制使用 IPV4，以查看其 IPV6 是否有問題。我還嘗試刪除所有這些 ppa 並再次添加它們。
答案1
當我遇到這種情況時（偶爾沒有網路更改），我發現使用apt-get而不是apt有效。
答案2
好吧，當我連接到大學宿舍的網路時，現在已經解決了。可能是 ISP 或路由器出現問題。
更新：
好吧，我實際上發現了這個問題，我認為將其添加到此處的討論中會很好，這樣其他人可能會發現它很有幫助。
問題是我的家庭互聯網調製解調器未啟用 ipv6。所以我進入調製解調器配置 IP 位址並啟用它，我家的問題也解決了。
也可能是您的 ISP 不支援 ipv6，印度的 BSNL 就是這種情況，所以也要注意這一點。