If you click 'Publish' button in your Welcome Message flow, but an error from the system shows up which makes publishing impossible, be sure to read what the error message says. It will point out the problem that has to be fixed. For example, if you get the error message below, this means that you have a button in a message that doesn't have any reply attached to it:
Attaching the reply to the button will solve the issue and then you'll be able to publish the flow.
If the error you're seeing is saying something else and you can't figure out what the issue is exactly, try switching to Flow Builder view - in this case, when the error appears, the flow will automatically focus on the problematic block which will be highlighted in red. Seeing this block, it should become more clear what the issue might be.
Another problem may occur when you can't activate the Welcome Message that is already published. If you see the following error (screenshot below), most probably the issue is that you don't have a necessary Page Role on FB to activate the Welcome Message on this page. To fix the issue, you have to ask the page admin to give you the 'Admin' or 'Editor' Page Role on Facebook. When it's done, refresh permissions in ManyChat and try publishing the Welcome Message again.
In case you came across any other error message, or the instructions above didn't help, be sure to shoot a ticket to our Support Team.