Well, I don’t think I have solved whatever is the root problem, but I have managed to slap on enough bandaids to restore all my services. I was finally able to restore my mail service by restarting the postsrsd service. This, along with the other fixes, has solved my “Temporary Lookup Failure” and I am able to send/receive mails again. Special thanks to this post since my postfix logs were quite similar.
In Summary
When I reboot the server several services do not start (including all the yunohost services) and I often receive cannot connect to /var/run/nscd/socket error.
To get the server operational again, I take the following steps:
systemctl start dbus.servicesystemctl start postsrsdnano /etc/php/7.4/fpm/pool.d/synapse.confand change the user and group fromsynapsetomatrix-synapseyunohost service start *to start all YNH services
Again - there is definitely a deeper issue here, but hopefully these steps will be able to limp me along until the next major update, which I hope will solve the root cause.