I had an issue with OpenVPN on my iPhone that had started months ago. I am NOT an expert and just had to hunt around online. I found nothing that would correct the issue- recently updated, verified isp connection... etc...
I had even sat through over an hour with ATT support asking about port blocking for VPN's and they TOTALLY BS'd me about it, saying they DO NOT block vpn's.
Today I had a minute and was tethered to my iPhone with ATT service here in central TX and when I changed to UDP port 80 via Eddie's Protocol settings, ALL became well.
Further, I used the OpenVPN Config Generator, set to Advanced Mode and using protocol UDP 80, my iPnone on LTE will now connect AND send and receive data! UDP 443 IS blocked in my area...
I posted this to help others who may be having this issue with ATT AT&T LTE 4G blocking AirVPN data transmission, but still showing connected and eventually stalling out- ot not... 😕