Steps:
While in PC VR, select a user, and click "gift vrchat+" then with the 1 month option selected, press "purchase gift sub for XXX"
Issue:
After clicking this it often just spins, and nothing happens. No error messages or feedback on whether it failed or succeeded.
Other:
VRC is probably losing a lot of potential money from this. This whole process has a lot of unnecessary friction, and could be made better. A simple suggestion is to allow purchasing of VRC+ with VRChat credits to cut out all the third party stuff (steam, paypal, etc) so it can truly be a "1 button press" thing.
It's hard to debug since I don't want to hammer at an issue that costs real money, so I don't have more useful info. Sometimes it does succeed and works as intended, but that's rare.