Same ISP but one of us can't connect

Hello to the Pritunl community,
Due to the severe restrictions imposed on the Internet in my country (Iran), one of my friends and I bought a VPS service from Vultr and installed the Pritunl service on it to bypass these restrictions.
After configuring and starting the server, My friend was able to connect to the server easily And his IP was properly changed and all the restrictions on his internet were removed. But I could not connect.
And as mentioned in the title, we use exactly the same ISP, but we live in two different cities in Iran.
I would really appreciate it if anyone has any information to solve the problem.