I decided to move away from Trello and Jotform and use Google Sheets / Forms for my commissions instead. This way, I can manage everything in one place instead of hopping between different sites. The sheet works like a little database, and the front-end is a web app built with Apps Script. To avoid the headaches of hosting and CORS issues, everything is embedded here on Google Sites.
If you’re seeing the "Sorry, unable to open the file at this time” message, it’s most likely because you’re using Google Chrome with multiple Google accounts signed in on the same profile. Unfortunately, Google Apps Script (GAS) has a long-running issue where it gets confused when more than one account is active, so it can't reconcile which account to use when loading the scripts, which then prevents the pages from loading properly.
To fix this, you have two options:
Use a Chrome profile with only one Google account signed in, or;
Open the page(s) in a different browser.
It gives me more freedom on what info I want to store and how to show them compared to Trello, which required you to use paid plans / third-party power-ups to use things like custom fields. Using another Chrome profile with just one account logged in or using another browser may seem a little inconvenient if the pages don't load right, but I'll take that over relying on other services.
If you'd rather not deal with my web apps, I always update my clients through their preferred method of contact. The queue is just there for transparency and info management.