Tor won't start with seccomp sandbox when compiled with --enable-nss

After compiling tor with the --enable-nss flag, starting tor with "Sandbox 1" on torrc results on the following error:

May 06 21:47:46.198 [notice] Tor 0.4.4.0-alpha-dev (git-42dfcd0ae3f7a872) running on Linux with Libevent 2.1.8-stable, NSS 3.35, Zlib 1.2.11, Liblzma 5.2.2, and Libzstd 1.3.3.
May 06 21:47:46.198 [notice] Tor can't help you if you use it wrong! Learn how to be safe at https://www.torproject.org/download/download#warning
May 06 21:47:46.198 [notice] This version is not a stable Tor release. Expect more bugs than usual.
May 06 21:47:46.198 [notice] Read configuration file "/home/daniel/Desktop/torrc_sandbox".
May 06 21:47:46.200 [notice] Opening Socks listener on 127.0.0.1:9050
May 06 21:47:46.200 [notice] Opened Socks listener on 127.0.0.1:9050
May 06 21:47:46.000 [notice] Parsing GEOIP IPv4 file /usr/local/share/tor/geoip.
May 06 21:47:46.000 [notice] Parsing GEOIP IPv6 file /usr/local/share/tor/geoip6.
May 06 21:47:46.000 [warn] TLS error PR_NO_ACCESS_RIGHTS_ERROR while constructing a client TLS context: Access Denied
May 06 21:47:46.000 [err] Error creating TLS context for Tor client.
May 06 21:47:46.000 [err] Error initializing keys; exiting