Xbox One error code 0x8027025a is an error that usually occurs upon signing in or when opening an Xbox One app. The error may occur for a number of possible reasons including a sign-in issue with your profile, the application failed to load in the expected time, or there is a temporary problem with the Xbox Live service.
Some of the common fixes include:
Please see our in-depth walk-through solutions below.
If "Xbox One error code 0x8027025a" appears when signing in, the Xbox live server may be overwhelmed with the client requests. It is also possible that the Xbox Live server is currently undergoing server maintenance. To confirm, see link here.
If it has limited access or is down, wait for the server to recover.
If the HDD is found defective, order a new one or send the console to the Xbox service center.