Postfix actually got uninstalled while I was adding the spf records, no wonder I couldn't connect to the postfix server. I can connect now but the emails sent to outside my network aren't being delivered, only the ones sent inside the network. And the clients are still able to send even though only the server is supposed to be. mail.log says:
server postfix/qmgr: warning: connect to transport smtp: Connection refused
Maybe that's because the spf record is wrong?