I am using F-Droid 1.17.0 on a FP3+ with /e/OS 1.13-s.
Now, I want to install Umbrella (Security First - Umbrella) and added the repository via QR-code.
Only the repository does not become activated since last Tuesday though I have checked daily updates to no avail.
Do you have more info on what you did step-by-step and what error message you get, if any (preferably with a screenshot)? The following worked for me:
Scan QR code on Umbrella in a QR scanner app (like Binary Eye)
Copy the full URL that comes out of it to your clipboard (https://secfirst.org/fdroid/repo/?fingerprint=39EB57052F8D684514176819D1645F6A0A7BD943DBC31AB101949006AC0BC228)
Go to F-Droid → Settings → Repositories → Add and see F-Droid automatically read the address and fingerprint from your clipboard
Press Add
For me, this instantly worked on F-Droid 1.17.0. However, I couldn’t see the new app until I explicitly searched for Umbrella as it hasn’t been updated in 3 years and is therefore very far down the list.