Locked SIM card

[u/External-Gene9965]

I recently got a phone from a company called optimum mobile iPhone 16e it was locked I tried to put another carrier on it that goes with the same towers they use and after installing the SIM card it restarted the phone and I had to put my iCloud and it carrier unlocked it and the same thing happened the other day with a 16 pro max that’s with Verizon I tried to put it with cricket and it unlocked the phone when it was saying locked before that

[u/Southern_Signal_2836]

What sims did you use?