A single phone number can not register over 5 times for E1 trial subscription

[kaninteamsforthailand]

I've assigned to help companies in my country accomplishing E1 trial campaign. Then I have noticed my phone number can not register over 5 times for E1 trial subscription.

Does this problem happen because I've used single phone number many time or other problem?

[#2]

Just use a different phone number.