Can't get GRSync to work with MTP devices

I’ve used GRsync in the past to synchronize my photos between my phone and a backup on my computer. Now I want to synchronize my logseq files between phone & computer and for some reason it’s not working. I get an error when trying to open the destination location on my pixel 3:

The folder contents could not be displayed
Cannot change to folder because it is not local

I’m not clear on what the problem is here, or how to go about fixing it. Last time I did this, it just worked. I can access the phone’s storage via Files/MTP just fine, and manually transfer things that way. But having Rsync do the work would be much preferred.