Pitch of recorded material too low (after unconscious change of samplerate?)

Yesterday I recorded my guitar with Ardour 8.6. Over night I tinkered with Jack, Cadence and Raysession. When I opened my project today and wanted to add-record instruments, I realized that yesterdays recordings are all too low in pitch. It’s like I had recorded a too low tuned guitar.

I suppose it has to do with the sample rate of the project. Maybe I changed it outside Ardour when I did my experiments with Jack and Raysession? Is there a way to change the sample rate and thus to raise the pitch back to normal?

Using which backend, ALSA or JACK?

You have traditional jackd, not pipewire-jack?

Ardour will warn you if the session sample rate does not match the current system sample rate.
You can look at the beginning of the .ardour file for the project and it will indicate the sample rate.
Check that and compare your currently selected sample rate.