I get these constantly and i got annoyed so i figured out a fix. This happens when firestorm can't fetch get_grid_info url for a grid. It's not the grid list in preferences, it's landmarks, groups, and maybe friends. Anyway the default toast is "OKCANCEL" and i changed it to "OKIGNORE". this way the user still has preference and and option to disable or enable the warnings.
in this example i'm using ENGLISH so you have to pick the language you use. Or change all of them, which might be work for nothing if you only use one language.
edit as Administrator: C:\Program Files\FirestormOS-Releasex64\skins\default\xui\en\notifications.xml
(note "en" directory is for english, the other languages are there. also change the path depending on your installation)
find "CantAddGrid" in the file. Change the usetemplate to OKIGNORE like this:
usetemplate
ignoretext="Warn when a remote grid cannot be reached."
name="okignore"
yestext="OK"/>
note: there is a bracket before usetemplate - osw can't display b/c of html escape i suppose
restart firestorm. the next time you get that warning there's a checkbox to ignore future warnings, if you check it and hit ok you won't see those anymore.
https://gyazo.com/a82f542c9c2692cb3238032d8c27e0fd