python – I am making a server-client chatting app and I am getting this error

I am making a server-client chatting app and I am getting this error on the server:

127.0.0.1 connected
Exception ignored in thread started by: <function clientthread at 0x00000275F407F040>
Traceback (most recent call last):
File "D:client-server stuffchatroom 2serverServer.py", line 65, in clientthread
conn.send("Welcome to this chatroom!")
TypeError: a bytes-like object is required, not 'str'

and this error on the client:

Traceback (most recent call last):
File "D:client-server stuffchatroom 2clientclient.py", line 27, in <module>
read_sockets,write_socket, error_socket = select.select(sockets_list,(),())
OSError: (WinError 10038) An operation was attempted on something that is not a socket

my code is on github here: https://github.com/NotCoolKiwiTeam/Project-EnderChat