Login issue with Microsoft or is it my phone ?

Try these checks first:

1. Make sure the code is being sent to the correct method.
   • Email codes are only sent to the primary alias or another email added as a sign-in verification method.
   • If the masked phone number or email does not look right, sign in to the Security basics page and select Update info.
2. On the iPhone, check whether texts from unknown numbers are blocked.
   • If they are, change that setting and then choose I don't have a code to request another code.
3. Check for phone-side delivery issues.
   • Make sure the message inbox is not full.
   • If the messaging app is malfunctioning, troubleshoot it or try receiving the SMS again.
   • If a VOIP number was added, replace it with a mobile phone number, because VOIP numbers cannot be used to sign in or receive verification codes.
4. If the code is sent by email, check Junk/Spam.
   • Valid Microsoft verification emails come from @accountprotection.microsoft.com.
   • Mark that sender as trusted.
5. Avoid repeated code requests.
   • Excessive or repetitive requests can cause Microsoft to temporarily stop sending codes.
   • Unusual activity or heavy compromised traffic in a region can also delay delivery for a period of time.
6. If the current verification method is unavailable, choose another method.
   • If available, select Use a different verification method.
   • If access to the listed phone or email is lost, select I don't have any of these and follow the prompts.
7. If signed in somewhere else and the password is known, add another sign-in method.
   • Go to the Advanced security options page.
   • Select Add a new way to sign in or verify.
   • Confirm the new number or email with the code sent to it.
   • Do not change all security info at the same time, because the account may be restricted for 30 days.
8. If no codes arrive at all, use Microsoft recovery tools.
   • Use the Sign-in Helper tool.
   • If still blocked, use Contact Microsoft Support.
   • Support agents cannot send verification codes or change account details.

References:

• Troubleshoot Microsoft verification code issues
• I can't sign in to my Microsoft account
• Microsoft account security info & verification codes