Save button greyed out cant save credentials?!

Hi everyone, so I have had no troubble adding credentials to my excel online sharepoint data sources. except one.

From the liniage view etc, it says its fine but from the gateway its telling me "credentials missing", so i go to settings from the "manage gateways" and try to add the credentials  needed, that worked for alllllll other files of the same format and origins. but the save will not highlight on one particular data spreadsheet.

I cant click save and only get the "cancel or discard changes" options if i click the x, and no option to "save changes" or anthing, all the other data sets work fine and are "online"

All seem ok here too! along with all saying "connected" in liniage. even for the set that apparently has "credentials missing" in the manage gateways. 

Is this a bug? How can i fix this without having to remove and re add and re authenticate the many many files i have 😞 

also no error messages when refreshing the data manually

How can i resolve this? is it even an issue? or something i can just ignore as an annoying glitch but dosent effect the report?