I am not sure whether the server information is correct. Please suggest. I have got the error message below when typing apt update.
-- message --
Get:6
http://apt.myvestacp.com/buster buster InRelease [2,305 B]
Err:6
http://apt.myvestacp.com/buster buster InRelease
The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 88807D4B2221338C
Fetched 2,305 B in 1s (1,929 B/s)
Reading package lists... Done
Building dependency tree
Reading state information... Done
115 packages can be upgraded. Run 'apt list --upgradable' to see them.
W: An error occurred during the signature verification. The repository is not updated and the previous index files will be used. GPG error:
http://apt.myvestacp.com/buster buster InRelease: The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 88807D4B2221338C
W: Failed to fetch
http://apt.myvestacp.com/buster/dists/buster/InRelease The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 88807D4B2221338C
W: Some index files failed to download. They have been ignored, or old ones used instead.