cannot create new item and publish list after editing

Mar 20 at 8:03 PM
hi all

i cannot add new item in banner list and also cannot publish it

i get error The server was unable to save the form at this time. Please try again.

i used banner with SharePoint online and it's worked perfectly

also i cannot open bright banner app from client machines but when i open it from server it's working

any idea?

thanks in advance