Maybe he blocked you
What could cause this?

I can't even chat or message this player
It could be as a result of unstable internet connection. Resending or typing the message again should work.

I can't even chat or message this player
It could be as a result of unstable internet connection. Resending or typing the message again should work.
this user has removed every frnds and left all clubs, i think there r some options to disable chats and message from others, this user was very responsible to the club.....

I can't even chat or message this player
It could be as a result of unstable internet connection. Resending or typing the message again should work.
this user has removed every frnds and left all clubs, i think there r some options to disable chats and message from others, this user was very responsible to the club.....
has only 1 frnd rn

I can't even chat or message this player
It could be as a result of unstable internet connection. Resending or typing the message again should work.
It is internet connection, or sometimes chess.com has a temporary bug/glitch with messages (server related?) and I get their message failed sometimes. It mostly happens in Connect Messages.
Also, it isn't that they blocked you. If they had, it would give another message about how you are blocked and it wouldn't even give the option of typing a message.
I can't even chat or message this player