I have been experiencing the same Error Message, "We can't complete your request right now. Lo sentimos. Please try again later." since the beginnig of December. I have tried all of the solutions provided multiple times on my iPhone. I haven't been able to access the Verizon Up page at all. I've missed all of the holiday rewards and can't access the page to receive my monthly reward.
I've called the Verizon Up help desk and the general Verizon support, neither have been able to help correct the problem. I was told a ticket would be submitted to try to correct your system, but that was over a week ago.