Upon inspection of the shower, noticed that no water was coming out when turned. It was determined the the problem could be coming from the cartridge because do to the heavy amount on calcification on the trim. It took a while to pull the cartridge because half of it was stuck inside the shower valve but after a while was finally able to fully remove the cartridge from the valve. I inspected the inside of the valve to see if there was major damage but mainly found a lot of what seemed to be dirt in the line. Tried my best cleaning it out by opening up the main valve to wash out whatever was inside and took a rag and wiped it out as well. I put in the new cartridge and tested it out and everything seems to be working good again. Unfortunately with so much dirt in the valve, we cannot guarantee the issue will be solved long term. What I would recommend is to replace the shower valve entirely, with a new trim.