When downloading CODEX, it asks for a phone number to login.
For UK customers, Codex adds a ZERO after the +44 which does NOT work. So authentication is impossible.
Example: I enter +44 7501 234567 but the system turns it to +44 07501 234567 which does NOT work. I never receive the WhatsApp message and I cannot sign in, using this method.
If Codex is automatically adding the 0 after +44, that sounds to me like a phone-number formatting/authentication bug.
I’d suggest reporting it through Help Center/Codex support.
I think that’s the best option for you, to get this sorted.
When will they fix the issue with the extra “0” being added to phone numbers?
This other problem might be the same.
These two topics are slightly different, the one you linked was about SMS not being visible option for signing in to codex. This seems to be a bug where extra “0” is being added to the number.
@videcode is it also an UK number or from a different country? That would be helpful to know.
The best thing is to contact support through Help center. I think this issue is something that OAI support/staff needs to look into.
from Ukraine. i’m having the same issue—an extra “0” in the number.
but this problem only happens when logging in via a computer. when logging in via a phone, the extra “0” doesn’t show up. 
if you’re having trouble with this, keep that in mind.
Thanks for the information!
Then I think this should definitely be looked into by OAI.
Good thing tho that you can login with your phone.
That definitely sounds odd. Could you please open a support ticket so the team can take a closer look and help get this sorted out? Thanks!