Problems with Jitsi Meet when some of the participants use Firefox / Android

I’ve recently installed Jitsi Meet following the guide at Github, up to the advanced configuration where I only set the PUBLIC_ADDRESS due to the VPS not being connected to a private network.
I have allowed ports 80, 443, 4443 and 10000 through the Firewall, and that enabled me to create conferences of more than 2 people after having some problems with that before.

When inviting someone that uses Firefox, that person is unable to hear us or to talk, and appears as being muted.
Something similar happened after inviting a user in Android, but this time while using meet.jit.si. At first we were able to see the camera, but then he was unable to speak even though he could hear us, and no camera was shown.

For the Firefox case, I tried looking for problematic logs in jvb.log, and found the following at what I think are the times we tried inviting a user with Firefox:

Summary

JVB 2019-09-24 11:42:16.015 WARNING: [5165] org.jitsi.videobridge.AbstractEndpointMessageTransport.log() Unable to find endpoint c161c078 to send EndpointMessage
JVB 2019-09-24 11:42:36.015 WARNING: [5215] org.jitsi.videobridge.AbstractEndpointMessageTransport.log() Unable to find endpoint c161c078 to send EndpointMessage
JVB 2019-09-24 11:42:46.018 WARNING: [5239] org.jitsi.videobridge.AbstractEndpointMessageTransport.log() Unable to find endpoint c161c078 to send EndpointMessage
JVB 2019-09-24 11:42:56.017 WARNING: [5264] org.jitsi.videobridge.AbstractEndpointMessageTransport.log() Unable to find endpoint c161c078 to send EndpointMessage
JVB 2019-09-24 11:43:06.015 WARNING: [5288] org.jitsi.videobridge.AbstractEndpointMessageTransport.log() Unable to find endpoint c161c078 to send EndpointMessage
JVB 2019-09-24 12:09:00.004 WARNING: [8625] org.jitsi.videobridge.AbstractEndpointMessageTransport.log() Unable to find endpoint d3a385ec to send EndpointMessage
JVB 2019-09-24 12:09:10.000 WARNING: [8649] org.jitsi.videobridge.AbstractEndpointMessageTransport.log() Unable to find endpoint d3a385ec to send EndpointMessage
JVB 2019-09-24 12:09:19.997 WARNING: [8673] org.jitsi.videobridge.AbstractEndpointMessageTransport.log() Unable to find endpoint d3a385ec to send EndpointMessage
JVB 2019-09-24 12:09:29.992 WARNING: [8697] org.jitsi.videobridge.AbstractEndpointMessageTransport.log() Unable to find endpoint d3a385ec to send EndpointMessage
JVB 2019-09-24 12:09:39.990 WARNING: [8721] org.jitsi.videobridge.AbstractEndpointMessageTransport.log() Unable to find endpoint d3a385ec to send EndpointMessage
JVB 2019-09-24 12:09:49.992 WARNING: [8746] org.jitsi.videobridge.AbstractEndpointMessageTransport.log() Unable to find endpoint d3a385ec to send EndpointMessage
JVB 2019-09-24 12:09:59.996 WARNING: [8770] org.jitsi.videobridge.AbstractEndpointMessageTransport.log() Unable to find endpoint d3a385ec to send EndpointMessage
JVB 2019-09-24 12:10:09.996 WARNING: [8794] org.jitsi.videobridge.AbstractEndpointMessageTransport.log() Unable to find endpoint d3a385ec to send EndpointMessage
JVB 2019-09-24 12:10:19.996 WARNING: [8818] org.jitsi.videobridge.AbstractEndpointMessageTransport.log() Unable to find endpoint d3a385ec to send EndpointMessage
JVB 2019-09-24 12:10:29.997 WARNING: [8842] org.jitsi.videobridge.AbstractEndpointMessageTransport.log() Unable to find endpoint d3a385ec to send EndpointMessage
JVB 2019-09-24 12:10:39.997 WARNING: [8866] org.jitsi.videobridge.AbstractEndpointMessageTransport.log() Unable to find endpoint d3a385ec to send EndpointMessage
JVB 2019-09-24 12:10:49.997 WARNING: [8891] org.jitsi.videobridge.AbstractEndpointMessageTransport.log() Unable to find endpoint d3a385ec to send EndpointMessage
JVB 2019-09-24 12:10:59.997 WARNING: [8915] org.jitsi.videobridge.AbstractEndpointMessageTransport.log() Unable to find endpoint d3a385ec to send EndpointMessage
JVB 2019-09-24 12:11:09.996 WARNING: [8939] org.jitsi.videobridge.AbstractEndpointMessageTransport.log() Unable to find endpoint d3a385ec to send EndpointMessage
JVB 2019-09-24 12:11:19.996 WARNING: [8963] org.jitsi.videobridge.AbstractEndpointMessageTransport.log() Unable to find endpoint d3a385ec to send EndpointMessage
JVB 2019-09-24 12:11:29.993 WARNING: [8987] org.jitsi.videobridge.AbstractEndpointMessageTransport.log() Unable to find endpoint d3a385ec to send EndpointMessage
JVB 2019-09-24 12:11:39.991 WARNING: [9011] org.jitsi.videobridge.AbstractEndpointMessageTransport.log() Unable to find endpoint d3a385ec to send EndpointMessage
JVB 2019-09-24 12:11:49.989 WARNING: [9036] org.jitsi.videobridge.AbstractEndpointMessageTransport.log() Unable to find endpoint d3a385ec to send EndpointMessage
JVB 2019-09-24 12:11:59.988 WARNING: [9060] org.jitsi.videobridge.AbstractEndpointMessageTransport.log() Unable to find endpoint d3a385ec to send EndpointMessage
JVB 2019-09-24 12:12:09.985 WARNING: [9086] org.jitsi.videobridge.AbstractEndpointMessageTransport.log() Unable to find endpoint d3a385ec to send EndpointMessage
JVB 2019-09-24 12:12:19.984 WARNING: [9110] org.jitsi.videobridge.AbstractEndpointMessageTransport.log() Unable to find endpoint d3a385ec to send EndpointMessage
JVB 2019-09-24 12:12:29.981 WARNING: [9134] org.jitsi.videobridge.AbstractEndpointMessageTransport.log() Unable to find endpoint d3a385ec to send EndpointMessage
JVB 2019-09-24 12:12:39.981 WARNING: [9158] org.jitsi.videobridge.AbstractEndpointMessageTransport.log() Unable to find endpoint d3a385ec to send EndpointMessage
JVB 2019-09-24 12:12:49.977 WARNING: [9183] org.jitsi.videobridge.AbstractEndpointMessageTransport.log() Unable to find endpoint d3a385ec to send EndpointMessage
JVB 2019-09-24 12:13:03.019 WARNING: [9210] org.jitsi.videobridge.AbstractEndpointMessageTransport.log() Unable to find endpoint abbf49d5 to send EndpointMessage
JVB 2019-09-24 12:26:43.643 WARNING: [243] org.jitsi.videobridge.AbstractEndpointMessageTransport.log() Unable to find endpoint d6a39610 to send EndpointMessage
JVB 2019-09-24 12:26:53.644 WARNING: [273] org.jitsi.videobridge.AbstractEndpointMessageTransport.log() Unable to find endpoint d6a39610 to send EndpointMessage
JVB 2019-09-24 12:27:03.643 WARNING: [300] org.jitsi.videobridge.AbstractEndpointMessageTransport.log() Unable to find endpoint d6a39610 to send EndpointMessage
JVB 2019-09-24 12:27:13.645 WARNING: [326] org.jitsi.videobridge.AbstractEndpointMessageTransport.log() Unable to find endpoint d6a39610 to send EndpointMessage
JVB 2019-09-24 12:27:23.645 WARNING: [353] org.jitsi.videobridge.AbstractEndpointMessageTransport.log() Unable to find endpoint d6a39610 to send EndpointMessage
JVB 2019-09-24 12:27:33.647 WARNING: [378] org.jitsi.videobridge.AbstractEndpointMessageTransport.log() Unable to find endpoint d6a39610 to send EndpointMessage
JVB 2019-09-24 12:27:43.645 WARNING: [402] org.jitsi.videobridge.AbstractEndpointMessageTransport.log() Unable to find endpoint d6a39610 to send EndpointMessage
JVB 2019-09-24 12:27:53.645 WARNING: [426] org.jitsi.videobridge.AbstractEndpointMessageTransport.log() Unable to find endpoint d6a39610 to send EndpointMessage
JVB 2019-09-24 12:28:03.648 WARNING: [450] org.jitsi.videobridge.AbstractEndpointMessageTransport.log() Unable to find endpoint d6a39610 to send EndpointMessage
JVB 2019-09-24 12:28:13.648 WARNING: [476] org.jitsi.videobridge.AbstractEndpointMessageTransport.log() Unable to find endpoint d6a39610 to send EndpointMessage
JVB 2019-09-24 12:28:23.647 WARNING: [500] org.jitsi.videobridge.AbstractEndpointMessageTransport.log() Unable to find endpoint d6a39610 to send EndpointMessage
JVB 2019-09-24 12:28:33.646 WARNING: [525] org.jitsi.videobridge.AbstractEndpointMessageTransport.log() Unable to find endpoint d6a39610 to send EndpointMessage
JVB 2019-09-24 12:28:43.648 WARNING: [549] org.jitsi.videobridge.AbstractEndpointMessageTransport.log() Unable to find endpoint d6a39610 to send EndpointMessage
JVB 2019-09-24 17:50:28.331 WARNING: [8052] org.jitsi.videobridge.AbstractEndpointMessageTransport.log() Unable to find endpoint 86d2d70c to send EndpointMessage
JVB 2019-09-24 17:50:28.375 WARNING: [8053] org.jitsi.videobridge.AbstractEndpointMessageTransport.log() Unable to find endpoint 86d2d70c to send EndpointMessage
JVB 2019-09-24 17:51:52.921 WARNING: [8459] org.jitsi.videobridge.AbstractEndpointMessageTransport.log() Unable to find endpoint 2c012665 to send EndpointMessage
JVB 2019-09-24 17:51:52.946 WARNING: [8460] org.jitsi.videobridge.AbstractEndpointMessageTransport.log() Unable to find endpoint 2c012665 to send EndpointMessage
JVB 2019-09-24 17:51:57.637 WARNING: [8485] org.jitsi.videobridge.AbstractEndpointMessageTransport.log() Unable to find endpoint 1fced4a5 to send EndpointMessage
JVB 2019-09-24 17:51:57.660 WARNING: [8486] org.jitsi.videobridge.AbstractEndpointMessageTransport.log() Unable to find endpoint 1fced4a5 to send EndpointMessage
JVB 2019-09-24 17:57:56.820 WARNING: [9621] org.jitsi.videobridge.AbstractEndpointMessageTransport.log() Unable to find endpoint 52ac937c to send EndpointMessage
JVB 2019-09-24 17:58:06.819 WARNING: [9645] org.jitsi.videobridge.AbstractEndpointMessageTransport.log() Unable to find endpoint 52ac937c to send EndpointMessage
JVB 2019-09-24 17:58:16.819 WARNING: [9669] org.jitsi.videobridge.AbstractEndpointMessageTransport.log() Unable to find endpoint 52ac937c to send EndpointMessage
JVB 2019-09-24 17:58:26.817 WARNING: [9693] org.jitsi.videobridge.AbstractEndpointMessageTransport.log() Unable to find endpoint 52ac937c to send EndpointMessage
JVB 2019-09-24 17:58:36.816 WARNING: [9717] org.jitsi.videobridge.AbstractEndpointMessageTransport.log() Unable to find endpoint 52ac937c to send EndpointMessage
JVB 2019-09-24 17:58:46.816 WARNING: [9742] org.jitsi.videobridge.AbstractEndpointMessageTransport.log() Unable to find endpoint 52ac937c to send EndpointMessage
JVB 2019-09-24 17:58:56.815 WARNING: [9766] org.jitsi.videobridge.AbstractEndpointMessageTransport.log() Unable to find endpoint 52ac937c to send EndpointMessage
JVB 2019-09-24 17:59:06.814 WARNING: [9790] org.jitsi.videobridge.AbstractEndpointMessageTransport.log() Unable to find endpoint 52ac937c to send EndpointMessage
JVB 2019-09-24 18:00:40.670 WARNING: [10019] org.jitsi.videobridge.AbstractEndpointMessageTransport.log() Unable to find endpoint 8a225fe1 to send EndpointMessage
JVB 2019-09-24 18:00:50.669 WARNING: [10046] org.jitsi.videobridge.AbstractEndpointMessageTransport.log() Unable to find endpoint 8a225fe1 to send EndpointMessage
JVB 2019-09-24 18:01:00.667 WARNING: [10070] org.jitsi.videobridge.AbstractEndpointMessageTransport.log() Unable to find endpoint 8a225fe1 to send EndpointMessage
JVB 2019-09-24 18:01:11.567 WARNING: [10094] org.jitsi.videobridge.AbstractEndpointMessageTransport.log() Unable to find endpoint 8a225fe1 to send EndpointMessage

For the record, I have already set
enableFirefoxSimulcast: true
and the version I am using is straight from the repository in Ubuntu 18.04.

Best regards.