Unable to make a new folder

[#1]

go thru usual sequence for creating a new folder in email 

insert name for new folder when i click save then get red message

" an error occurred while saving "

also my folder name is now a blue highlighted name

have attempted closing and trying again    no difference

Kenm    xxxx@xxxx.plus.com

[#2 · Accepted solution]

Just tried again and a second box has now appeared under the name of folder box 

clicked in their also for inbox all worked well 

where did the second box go to earlier

Kenm