Discord replaces when you’ve been kicked, then comes back in a few minutes
When servers are under attack, the attackers will often use programs that scramble how data is getting to where it needs to be, so discord may appear to be “connecting” for a long time. This can also happen on networks with significant lag (think gaming or streaming from another country). In this case just keep checking and eventually you’ll reconnect. If you have an ADSL connection or cable internet and that doesn’t work, you’re likely out of luck and need more technical assistance – typically either resetting your modem/router or trying other configurations.