The default is 1234 if I understand that it's the Sim lock pin. But I guess not. After doing some reading, I see that call barring is a Samsung specific feature within phone settings. 0000 should be default? Where did you get your phone from?

Edit: I do see 1919 is a possibility for default?

No, it is not SIM lock pin, it is Phone App → Settings → Supplementary Services → Call Barring
I have Koodo sim card on Samsung Note 10+. There is a password which I don’t have. Sometimes i have an error: Failed to read data. Something went wrong. Check your sim card and network connection when I am going in Call Barring menu, should be due to password. Don’t tell me 1234 password works for you for this menu. This is sim pin, and should not be a password for call barring feature. 

When I do change, it is asking a password. When I enter it, 1919 for example, I have popup Failed to read data. Call barring rejected. 
I tried it to do as well on not koodo phone with the koodo sim - the same rejection. Must be koodo sim card related. 

Ok, I tried to use short code *33*password# (where i tried passwords 0000,1111,1234,5678,1919) which is the same as GUI based call barring for all outgoing call and call barring command was recognized, but I get an error “Connection problem or invalid MMI code”. 
I tried the same with other provider SIM card and it worked.  Hey, koodo, we need your help. 

Which carrier firmware are you using? Was it Koodo  (KDO) ?

I don’t think Koodo firmware offer the “call baring” feature. If you ran on another carrier firmware, you might not be able to get it working.

Having the same issue with the exact phone, Samsung Note 10+. I went to unlock my phone and found it in a call to the USA. No clue how that happened and now will have to pay for the call. Is it the phone not allowing the barring or Koodo?

I’m not following how call barring is a Koodo issue. As far as I understand, it is a feature specific to Samsung phones. It’s surprising to me that you could remove call barring with another sim card, but a Koodo one will not work. I also used to have a note 10+ and never had this issue. I’ll flag a rep to see if they can help with the pin and if a callback is required or not for tech support if it’s a persistent issue.

@Goran , @Lucertola it is not Samsung phone function, from my understanding it is Android function which I see on all Android phones what I have access to.  Yes, on all my phones GUI doesn’t work regardless phone or SIM card, but it always work if I send a code *33*password#, but not for koodo SIM (please see my previous message). So, virtually it has nothing to do with a phone or phone origin, but with koodo support. Please see below what I received when I tried code *33*1234# or with all above passwords.

My phones which I tested are Samsung Note 10+, Samsung S22Ultra (both purchased directly from Samsung Canada and were originally activated on Koodo network), MI 10 Pro. Sim cards: koodo, Public mobile, videotron (cb works with short code), T-mobile (cb works with short code). 
So, it looks for me koodo doesn’t support call barring functionality or it is not activated. @Goran you should know better.

Note: In UI I have follow error when I am going in call barring menu.

And when I activated one or another call barring feature and enter any of passwords above, I get.

Please note, call barring is very useful feature. As a company, koodo can save a lot of hustle from me calling you and asking to remove one or another charge. And I believe I am not alone.  

Hello @yurkor! Thank you for taking the time to share your experience!

Unfortunately, the TELUS/Koodo network does not support the Call barring feature at the moment, however you can help us improve our network by sharing your feedback on our Ideas page here.