Intermittent outbound calls fail busy signal

I’ve inherited a Asterisk/FreePBX phone system. I’m not a phone system guy but I’m trying to get familiarized. Last night we stated experiencing issues where some outbound calls fail and the message on the phone just says “busy here”. I’m trying to trouble shoot this but really don’t have a clue where to start. I’m trying to look through the logs now. Any help pointing me in the right direction is greatly appreciated.

everyone is busy/congested at this time “dial failed for some reason with DIALSTATUS = Busy and HANGUPCAUSE = 17” is what I’m seeing in the log file so far

would be a good place to start. In general, something is busy, but we don’t know what because you didn’t provide that part of the message. Everything in the log is important when it comes to troubleshooting these things. We need a little more context around the message to give you more help.