[tor-relays] Too many connections warning

[Logforme]

I run the non-exit relay Logforme 
(855BC2DABE24C861CD887DB9B2E950424B49FC34).

Today I saw a new warning in my tor log file:
Dec 07 09:48:12.000 [warn] Failing because we have 32735 connections 
already. Please read doc/TUNING for guidance.

The relay runs on an old Debian Wheezy machine. Me being a Linux noob I 
tried to read the doc/TUNING document 
(https://gitweb.torproject.org/tor.git/tree/doc/TUNING) but the only 
information I deemed suitable for me was "Use ulimit -n", which I ran 
and it reported "1024". I guess that's not of interest for this warning.

Over the years I have added some stuff to my sysctl.conf file that I 
have picked up. Don't remember from where:
# Tor
net.core.rmem_max = 33554432
net.core.wmem_max = 33554432
net.ipv4.tcp_rmem = 4096 87380 33554432
net.ipv4.tcp_wmem = 4096 65536 33554432
net.core.rmem_default = 524287
net.core.wmem_default = 524287
net.core.optmem_max = 524287
net.core.netdev_max_backlog = 300000
net.ipv4.tcp_mem = 33554432 33554432 33554432
net.ipv4.tcp_max_orphans = 300000
net.ipv4.tcp_max_syn_backlog = 300000
net.ipv4.tcp_fin_timeout = 4
vm.min_free_kbytes = 65536
net.ipv4.tcp_keepalive_time = 60
net.ipv4.tcp_keepalive_intvl = 10
net.ipv4.tcp_keepalive_probes = 3
net.ipv4.ip_local_port_range = 1025 65530
net.core.somaxconn = 30720
net.ipv4.tcp_max_tw_buckets = 2000000
net.ipv4.tcp_timestamps = 0
net.ipv4.tcp_challenge_ack_limit = 999999999

None of the values seem to match the 32735 mentioned in the warning so 
I'm at a loss for what I am supposed to change.
Anyone knowledgeable of these things that can give me some pointers?