I’ve downloaded a bitcoin wallet and for some reason I’m not getting any connections, perhaps there are some problems with the nodes?
Yeah, it is always more likely it is rather you then the entire network. The incoming connections aren't necessary so neither is UPNP.
It is probably your firewall. Are you using your Internet from home, is it censored? More likely it is your computer. Perhaps an antivirus has a firewall that only allows certain ports or certain applications to connect. Try disabling your firewall on your antivirus software, if you are using Windows.
If not, then try installing the Tor browser and go to Settings->Options->Network and check "Connect through SOCKS5 proxy".
That will help if your Internet is censored from Bitcoin, which I don't know if any country does, but I know that some censor Tor so you might need to configure it to enable Tor bridges.