As @Gunner said, these shields are flakey and the quality control often leaves a lot to be desired. I’ve seen some that have multiple solder bridges across pins of the main chip and that work for some functions and not others.
There’s also an issue that they often work with newer routers/switches, but not with older ones (the opposite of the problem you’re having).
There a long debate on the subject here:
I thought I’d understood what was causing the issue with the shield not working with my older switch, but the last post by @distans throws some new ideas into the mix that I’ve not had chance to test.
This is good advice from @Costas and you shouldn’t be so dismissive. It echos some of what @distans is saying in the thread I linked to.
The people replying to this thread are all Blynk users like yourself, who are trying to assist you in solving your problem. If they ask you to post your code it’s for a good reason, not simply because that’s part of some script they are following.
Pete.