Add to List not working

About 70 percent of the time for the last month or so, when I try to add to one of my lists via a link, the list won’t add the item. Sometimes I try to add it repeatedly, and after 10 minutes or so, the item will be added. This isn’t sustainable, especially as a PRO user. Please let me know what’s happening. I’ve tried adding from the embedded list on my website, or by adding to the list on Listly. Same issue.