No_pubkey 2b844307be7e9e8c

W: Failed to fetch  
The following signatures couldn't be verified because the public key is not available: NO_PUBKEY 2B844307BE7E9E8C

I’ve tried re-adding the key as described in this document, but I keep getting the same issue. Can someone provide some advise?

sudo wget \
-O /usr/share/keyrings/seafile-keyring.asc

(Edit: I had previously linked to the syncing_client/install_linux_client help page, but I am not allowed to submit the document with links.)

You can see this No_pubkey b9aec3a21f035485

Thanks for letting me know.
I saw the title and saw the signature was different so I initially assumed it was old or otherwise unrelated. Now I know the issue came at the same time.