No sound at all the outputs of Qu-32 audio mixer

My Allen and Heath Qu-32 audio mixer had all of its outputs abruptly ceased producing sound. On the meters, input signals could be observed, but there was no sound coming from the outputs. How can I fix this issue?

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crwdns2889612:0crwdne2889612:0 0
crwdns2934285:0crwdne2934285:0