No sound after importing MIDI: what to check first
MeluMimi
https://melumimi.com/en/midi-no-sound

[ ] 1. Can you see notes?
Open the imported clip in the piano roll and find a passage containing notes. Start playback before that passage. An empty view or a playhead outside the clip does not establish that the whole file is empty. If no notes appear anywhere, compare the unchanged download with the public example or try the editor’s documented MIDI import command.

[ ] 2. Can the selected instrument make a sound?
MIDI stores musical events rather than recorded audio. Assign an available software instrument to the MIDI track. Test a note using that instrument’s own keys or the editor’s audition control. If that test is silent too, check playback before repeating audio-to-MIDI conversion.

[ ] 3. Check the track and output
Check whether the track is muted, its level is down, or another soloed track excludes it. Check that the intended instrument and audio output are selected. Compare with a project you already know plays correctly; preserve your current project and settings. A moving playhead or meter alone does not prove you can hear sound.

[ ] 4. If only the web preview is silent
Try the same public listening example in another regular browser and check that tab’s mute state. If the downloaded MIDI plays in an editor while one browser is silent, record that difference before deciding the conversion failed. Do not upload the recording again just to test browser sound.

[ ] 5. Sound is back, but it is a different instrument
Playback tone depends on the selected instrument. MIDI does not preserve the original recording’s voice or instrument sound. Use the original audio or separated audio for that sound; use MIDI when you want to edit musical notes. Renaming a .mid file to .wav does not render audio. Export audio from an editor after assigning a playable instrument.

[ ] What to keep if the issue remains
Note the editor and version, whether notes are visible, whether the instrument audition is audible, and whether the same MIDI works in a second editor. Share only the minimum information you choose through the existing contact page; remove private filenames, account details and unrelated windows from screenshots. A support report need not include the original recording.

Official MIDI playback reference
https://help.ableton.com/hc/en-us/articles/209068169-Understanding-MIDI-files