Cannot set notification sound in Textra

Hey;
I just bought a new phone - Moto G7 Optimo Maxx (Tracfone) with Android 9 Pie.
Before this phone I was using an LG Fiesta 2 with Android 7.

I have been using Textra ver 4.27 as my SMS app, and on Android 7 it worked perfectly.
But now on Android 9 I am unable to set the Notification Sound to anything but the default set for the phone.
For example, I have the Default Notification Sound (in Apps & Notifications > Notifications > Default Notification Sound) set to Captain's Log.

In Textra, I set the Notification Sound to Tinkerbell.
But whenever a text comes in, I get the Captain's Log sound.
If I set Default Notification to None, then I get no sound when a text arrives.

I uninstalled and re-installed Textra, but this had no effect.

Can anyone tell me what the problem is?

Thanks
ET

 

Um, well, that's the problem. I can set the default notification sound in Android settings, but in Textra itself, no matter what sound I set for notification, I always get the default (Android) notification sound. I should be able to set a specific sound for Textra, no? That is how it worked in Android 7 on my old phone.

 

Perhaps this is a limitation in the Moto G7 Optimo Maxx Tracfone? The phone is running Android 9 Pie. I may try Zedge, but I hesitate to install any app that is going to bug me with ads. I checked out their website, but it appears the 'premium' membership is for those who want to sell their art, not those of us who want to enjoy it without ads.
Can someone clarify this for me?
Thanks