Facing issue while adding azure resource manager in azure devops with trial account

Question

I have subscribed for a trial account (valid for 30 days) to some learning on azure devops, i want to run a pipeline which should push the image to ACR.
for that

1. I created a service principal, created a secret for it, then gave contributor access to this service principal
2. now when adding service connection, i select azure resource manager, it is not taking the manual way so i entered all the details manually, but not sure why the verify and verify and save button (at bottom) is greyed out.

can someone please help me