Metadata fixing

Is there a way to make Roon index again in order to complete missing metadata=mainly art cover ?
I mean I installed and it did a 90-95 percent work on my collection .Still there are albums without cover art and when I try identify album it doesn’t

Can you let me know a little more about what’s not working here @andrei_fried?

Some times its a spelling mistake and it wont budge till you nail it but some other times all seems good and still it gives no result . Here are three examples to ehat i mean in my library :
1-Status Quo - The collection 1987 - it apears that all is right but still can`t identify \ find the cover art
1-Ofrin - Rust & Velvet - the same
3-Elmore James - Slide Guitar master