The issue is the same for 3 different accounts out of 10 I purchased.
The are all aged 1.5 years and all have original email (GMAIL).
My process: 1 Instagram account per browser on a laptop. With Chrome, Chromium, Brave, Opera, Vivaldi, Slimjet and Iridium I can run several accounts, one at a time, for slow manual promotional reasons (IG accounts for models).
The 3 accounts with problems I have tried from a laptop with Chrome, Chromium or Brave browser several times on 4G and home WiFi. This laptop is fresh install of Ubuntu, never seen Instagram or GMail before these accounts.
4G LTE IPs are different each time. Home WiFi IP remains same for 2 accounts, different for the third account.
For the 1st account I have tried on 2015 Nexus 5x Android that was reset and fresh install of Instagram. Several tries on 4G and home WiFi and the code from Instagram seems to have never been sent as it never arrives in Gmail.
For the 1st account I have tried on 2017 LG G6 Android that was reset and fresh install of Instagram. Several tries on 4G and home WiFi and the code from Instagram seems to never have been sent as it never arrives in Gmail.
Each time I change devices I do receive the email from Instagram stating “We notice a login from a device you don’t usually use”. This email shows the device name and location. This is normal and expected.
Each time I wait 30 minutes and click to “Resend Code” and again the code never arrives.
NOW FOR THE CRAZY PART: Today I spoke with the seller I got the accounts from. He tried to login from his area (Netherlands) on LTE with Windows 10 laptop and Chrome browser. He got the same error, BUT when he requested the code it was sent and arrived at Gmail in 1 minute. He did not login, but he gave me the code and I was able to login fine on the same laptop / browser pair I have been trying for days!
Unable to understand what is happening here.