Tag errors while lunching the project

Hello everyone,

I am designing a project and when I am in preview or design mode, I do not have any problem but as soon as I lunch the project, the tags are going to be red with an error. I feel like the error is related to the database, but why they are all working in preview and design mode but not in lunch mode. Do you have any experience in this regard?
Thank you very much!

I got it working based on this thread:

The problem was with legacy database access.