I FIGURED IT OUT

For me it was happening because I could not see the Product/Service column in the table when trying to create a recurring transaction template. I imagine the hidden error was something like "put in a product/service" but it wasn't visible because the column wasn't. To fix:

1. Go to the gear in QB, under Your Company select Account and settings.

2. On the Sales tab at left, make sure "Show Product/Service column on sales forms" is on.

3. Try again.

I tried everything else listed here about clearing cache and incognito browser. This was the only thing that worked. Good luck.

QB - now that a retired QA engineer has found the bug, tell your engineers to fix this.