Since the certificate has expired, I tried to remove the original certificate. After creating a new certificate, I opened my project and there was a problem of removing the certificate. Xcode version：11.3 After I installed the certificate, open the project. Xcode will automatically create a development certificate, and I can run my project normally. But when I opened other projects of my team, the following problems occurred: Revoke certificate Your account already has a signing certificate for this machine but it is not present in your keychain. To create a new one, you must first revoke the existing certificate. After clicking revoke, I removed the original development certificate and recreated a new one. My current project can run normally, but the problem still occurs when I open other projects. xcode cannot recognize my certificate. How to solve this problem? (The first time I asked a question, I was still looking for a way to upload the question.)