SSL_accept stops

[mr-V-I-k-t-O-r]

i write multythread web server and it works fine but after some hours(from 2 to 50) https stops answer, but http is continue do it. I try to attach to program by gdb and thread with https clients handler is stops on function SSL_accept, i mean that thread stops somewhere inside this function.
i try to add thread which call shutdown function for socket which set in SSL if SSL_accept is dont stops for 10s or more, but it isn`t help

this is gdb's bt result

#0 __libc_read (nbytes=5, buf=0x556d64e5d003, fd=15) at ../sysdeps/unix/sysv/linux/read.c:26

#1 __libc_read (fd=15, buf=buf@entry=0x556d64e5d003, nbytes=nbytes@entry=5) at ../sysdeps/unix/sysv/linux/read.c:24

#2 0x00007fdf08d4ae89 in read (__nbytes=5, __buf=0x556d64e5d003, __fd=) at /usr/include/x86_64-linux-gnu/bits/unistd.h:44

#3 sock_read (b=0x556d64f66d20, out=0x556d64e5d003 "\026\003\001", outl=5) at ../../crypto/bio/bss_sock.c:138

#4 0x00007fdf08d4649d in BIO_read (b=0x556d64f66d20, out=out@entry=0x556d64e5d003, outl=outl@entry=5) at ../../crypto/bio/bio_lib.c:274

#5 0x00007fdf08eb5feb in ssl3_read_n (s=s@entry=0x556d63ce7d10, n=n@entry=5, max=5, extend=extend@entry=0) at ../../ssl/ssl_pkt.c:249

#6 0x00007fdf08eb6255 in ssl3_packet_read (s=s@entry=0x556d63ce7d10, plen=plen@entry=5) at ../../ssl/ssl_pkt.c:291

#7 0x00007fdf08eb7165 in ssl3_get_record (s=0x556d63ce7d10) at ../../ssl/ssl_pkt.c:348

#8 ssl3_read_bytes (s=0x556d63ce7d10, type=22, buf=0x556d639f0000 "\016", len=4, peek=0) at ../../ssl/ssl_pkt.c:982

#9 0x00007fdf08ea8291 in ssl3_get_message (s=0x556d63ce7d10, st1=, stn=8593, mt=16, max=2048, ok=0x7fdf07c4fa34) at ../../ssl/ssl_both.c:471

#10 0x00007fdf08ebcf40 in ssl3_get_client_key_exchange (s=s@entry=0x556d63ce7d10) at ../../ssl/ssl_srvr.c:2044

#11 0x00007fdf08ebf3e4 in ssl3_accept (s=0x556d63ce7d10) at ../../ssl/ssl_srvr.c:536

where is can be reason?