Invalid Phone when Signup Steemit

I get a lot of messages from friends who I invite to join Steemit. When they register and enter a cell phone number. The message Phone Invalid appears

They've tried registering different cell phone numbers but the same thing keeps coming up. Even their parents' and grandfather's numbers were impossible to use to register. So funny.

I was very troubled by this because I was part of the #Promo-steem team, and they failed to register for Steemit and became lazy to join because the same error appeared.

Is there a solution about this?

I'm trying to register an Indonesian number with the code + 62. In Indonesia, every cell phone number always begins with 08xx-xxxx-xxxx. Usually a cell phone number consists of 10-12 digits. For example, the number 081234567890 will be changed to +6281234557890

What about you when you register for Steemit?