I'm having the same problem since the last iphone app update several weeks ago. I have called in to tech support 3 times. The 1st time I was told by a person reading a script to use all sorts of different services available on PayPal and that it wasn't possible for anyone to log in via their mobile number. I insisted on speaking to someone at a higher level. He said someone would contact me within a few days. No one called. I called in again a week later on 10/30/14. There was no record of my previous call. I explained once again I can log in successfully 1 time, and then any time after that, I must power off my iphone before I can log in again via my email or mobile number. Once I log out, I cannot log back in again until I power off my phone. I have un-installed and re-installed the PayPal app several times. I have tried it while on my cellular network and while on wi-fi.
During call #2, they had me try logging in while on the phone with them and they said they could not see my attempts to log in. They gave me a ticket number and said someone would contact me within a few days to follow up.
Nearly 2 weeks go by and still no call from PayPal. I contact them once again on 11/13/14. They say my ticket was "canceled" and there was no reason stated. I was transferred to 2nd level support. He too could not see a reason for it being canceled and seemed genuinely willing to help resolve this issue, but it was not his skillset to do so. He then transferred me to a supervisor. "Brad" told me that they do not follow-up on tickets and do not return calls to customers. He said he has not heard of this problem before and that since I am the only one who has this problem, it is a problem with my network. I asked what department he was in and he claimed he was in the technical support department. I strongly urged him to escalate this matter and he made it clear he had no intention on doing so as I am the only one with this problem and for me to have a good evening.
Wow. Thank you PayPal.
