Hi! I’m trying to create an app, where people can sell and buy products. When someone wants to sell smth, he creates an announcement (is it the right word?) where he writes down all information about the product. Then this information is saved in Google sheets. So, in my blocks, rowid_list obtains all row ids of announcements. First, I thought that my for loop isn’t working. After, I tried to check it using labels. And I came to the conclusion that “get value from data source” block isn’t working. Every time the loop gets to this block, it just stops working. What problem is there? How can I solve it? Thank you for your answers in advance. 
I’m not sure how you got the screenshot so small but I can’t read any of it. Can you post a larger version? You should just be able to drag the image(s) into the post’s text box.
Does it look okay?