My barclays account is not allowing me to proceed with adding my bank to this app

Hello, usermohamed-24. 

Did you encounter an error code or messages when trying to add your Barclays bank account? Additional information helps me provide you the exact solution that you need.

In the meantime, I'll share some steps that can help you make sure that your mobile app is working correctly and will be able to link your bank account in QuickBooks Self-Employed. We can reset the application to refresh it. Follow the steps below:      

If you're using an Android device: 

1. Go to the More Options ⋮ menu.  
2. Select Settings.    
3. Tap Refresh Data, and then choose Yes.  

For iOS: 

1. Go to Help & Feedback at the top menu bar.   
2. Choose Reset App Data. Then Refresh.        

If it's works, let's go ahead and add your bank account in QuickBooks Self-Employed. To learn more about the process, you can refer to this article: Reconnect your bank account in QuickBooks Self-Employed. 

Let me know if you have additional questions about using the online banking feature. I'd be glad to answer them for you. Wishing you the best. Stay safe!