Identify the recorded failure
The original report describes the cannon making a puff of air without ejecting the player. Replies mention non-host sessions and busy servers, but those reports do not prove the sole cause of every cannon failure.
Record whether you saw and used an interaction prompt, entered the cannon, heard/saw the puff and then remained stuck. That sequence is more useful than a report that only says “cannon broken.”

Sources: Cannon report and replies
Check the documented fix against your build
The September announcement names two relevant changes: cannon softlocks are fixed, and players who previously rolled snowballs can now use cannons. If your report predates that update, retest on the current build before repeating an old workaround.
The May thread concerns Steam players. The official announcement also contains Xbox fixes, but the thread itself is not an Xbox reproduction record. Include the actual store and device when reporting a continuing failure.
Sources: September 21 official update · Cannon report and replies
Make one controlled retry
Update and retest the interaction
Use the current game update, return to a cannon and follow its visible interaction prompt. Note whether you rolled snowballs beforehand.
Use Unstuck if you remain locked
The September update adds Unstuck, which returns you to the last safe standing spot. This can release the position; it is not proof that the cannon’s cause is repaired.
Compare the session
If the host connection is struggling, note the pulsing indicator. Try the same interaction in your own arranged session if available.
Record a persistent failure
Keep the exact sequence, build, store, host/client role and outcome for a bug report.
For the host-connection symptom, use lobby connection help. The controls reference keeps interaction bindings separate from troubleshooting.
Sources: September 21 official update · Cannon report and replies