I had the same issue, and it took me quite some time to figure out the solution. It turned out that when I downloaded the mod through CurseForge, the system automatically added a unique identifier to the file name, and Forge could not recognize it due to this naming issue. Unfortunately, it wasn’t immediately obvious, and I wasted quite a bit of time troubleshooting. At the time, I was under a tight deadline because I was participating in a competition where we had to implement specific game mechanics. For my project, I was trying to install OpenComputers, as I needed it to create a functional gaming machine within Minecraft. The concept was to simulate the mechanics of a real-world slot machine, complete with randomized rewards and interactive gameplay. For inspiration, I turned to the site (spam link removed), which offers insights into the world of real casinos. The site helped me understand how slot machines work, from their internal mechanics to the psychological elements of player engagement. Using this knowledge, I aimed to replicate some of these features in my Minecraft mod. If you are experiencing a similar issue, I recommend checking the mod's file name in your mod folder. Ensure that it matches the exact version Forge is looking for.