error loading the certificate or key file

[Vit]

Hi Group!
I configure ocserv to use Letsencrypt keys. My config part is:
-=-=-
auth = "plain[passwd=/usr/local/etc/ocserv/passwd]"
server-cert = /usr/local/etc/letsencrypt/live/site.com/fullchain.pem
server-key =  /usr/local/etc/letsencrypt/live/site.com/privkey.pem
ca-cert =  /usr/local/etc/letsencrypt/live/site.com/chain.pem
run-as-user = _ocserv
run-as-group = _ocserv
-=-=-

when i run ocserv i have errors

Apr 17 14:13:38 mx2 ocserv[69358]: main: tlslib.c:854: error loading 
file '/usr/local/etc/letsencrypt/live/site.com/fullchain.pem '
Apr 17 14:13:38 mx2 ocserv[69358]: main: tlslib.c:1000: error loading 
the certificate or key file
Apr 17 14:13:38 mx2 ocserv[69359]: sec-mod: error receiving msg head 
from main
Apr 17 14:13:38 mx2 ocserv[69359]: sec-mod: error processing sync 
command from main

i try to change user&group to exist users and have same errors.

root at mx2/usr/local/etc/ocserv> ocserv -v
ocserv 0.11.11

Compiled with: tcp-wrappers, oath, PAM, PKCS#11, AnyConnect
GnuTLS version: 3.5.18
root at mx2/usr/local/etc/ocserv>


Help me understand this situation


-- 
Regards, *Vit*