Screen 1 button works, displays Notification dialog. However “Switches” screen does not open. Other buttons without Notification block also do not work.
Button is “enabled”.
I looked at a project that is like a year old and it also does not work with the same block. I’m stumped. 
It isn’t a good idea to open a notifier while opening another screen.That will definitely force your app not to open another screen.You need to open it on Switches initialization.
Also you aren’t switching between screens correctly.See here:
Also see this:
Suggestion seems reasonable, but it still does not open screen for me:
Button instantly changes its text to “Button was pressed.”
Does any error occur??
Nope, just sits there on Screen 1.
Check your scree name
Checked screen names a couple dozen times. 
Created a new project with 2 screens, one button per screen.
Here are Screen1 blocks:
Same blocks for Screen2:
No other code or buttons in the project.
Neither button changes screen.
Can you send an aia?
Swapped from Samsung S6 to S9. Still no joy. But I noticed it was switching very quickly from Screen1 to Screen2 and back to Screen1. 
So I took out the “Close Screen” blocks and now the open new screen works in both directions.
However, I went back to my S6 and it still doesn’t switch screens.
How can the open another screen block possibly work functionally differently for two different phones?
Included .aia for TestOpenScreen project. Thanks for your help!
TestOpenScreen.aia (3.0 KB)
it should work.That really sounds strange! Can you send a test aia?
Try building your app and see what happens on your s6…
To avoid this, use this blocks instead.
EDIT
Building an APK and downloading it to my S6…worked! 
Of course, the whole point for my use of the S6 is to test my design and blocks on the fly.
Is there a reason the code works for the APK, but not the Creator? 
/EDIT
Using the S9 with the Companion, the problem did go away with your suggested blocks.
However, the S6 is still problematic. Using the companion, it will NOT switch screens. 
I have been using block coding for a couple of years. I have wasted 6 hours on this one open screen problem. My point is that I have a fair amount of experience and I could not get it to work, even after reading docs and a guide and then a suggestion from a moderator. And it still doesn’t work for one of two similar Samsung phones. I’ve created a few apps and this is the first time my S6 has had a problem like this. Besides size, an S6 and an S9 are almost identical in execution.
Can you imagine what goes thru a newbie’s mind when trying to switch screens?
Seems to me that there should be a method to navigate from one screen to another without all this hassle. I was using another vendor and they have this:
I don’t recommend that vendor, but it least their “navigate to” block works flawlessly.
Another thing you may try is to clear data and cache from companion app on your s6.
Thanks for your help, btw.
Removed everything I could find regarding Android and Makeroid under Device Storage. Cache was empty.
Fired up Companion, opened Test menu, selected “Connect via USB”, hit Internal Error Cancel button 15 times and the TestOpenScreen project appears on my S6.
Fails. Opened Screen2 thru Screen selector, that button fails as well.
Frustration builds in this one. 
Never used usb connection and thereby can’t help you, usb is probably the culprit
Yes, neither do I, as it doesn’t seem to work on my PCs / notebooks (win7, win10).
In AI2, I almost always work with Companion via USB.
Btw, no problem to switch the screens in AI2 with Companion via USB connection (S6).
Thank-you for your help. 
What software version are you running on your S6, if you don’t mind my asking?
Running TestOpenScreen.aia:
MIT AI2 via USB works perfectly on my S6
Thunkable via USB works perfectly on my S6
Two Kodular projects via USB do not work on my S6. Still does not switch screens.
S6 via MIT AI2 Companion, works great. Connects and switches screens.
S6 via Thunkable Companion, works great. Connects and switches screens.
S6 via Kodular Companion, no work good. Back to the Error 1103, Unable to Post…etc.
I mean, if it’s an Android level or some such, what is the minimum requirement for Kodular?
My Samsung S9 works via USB and Companion, but it’s not really mine, belongs to my wife and she won’t let me have it except on weekends and evenings. 