Asterisk sporadically not processing DTMF

I can’t tell if its a load issue or a flaky hardware issue. Could anyone point me to where to begin troubleshooting? I’ll do my best to get you the information that I don’t know to provide presently.

Thanks

I turned on dtmf logging. When dtmf works, it shows up in the log message. When it doesn’t, there are no errors associated w/ DTMF at all.