The query criteria for the stored set may need to be corrected. Cause Proximity only works between two words, not between multiple words or phrases. The box contents which contain the problem search string are shown in the message. Then change your search so proximity operators are used only between two single words. Cause Your query criteria include a range search but the beginning of the range you specified is larger than the end of the range.
Solution Look for the range search.
It will have a colon in it. Then change the range search so the start of the range is to the left of the colon. You may be searching for text which actually has a colon in it, rather than attempting to perform a range search. Punctuation is not significant except in Code or UDC fields, so it's usually easier to omit punctuation in search text. The box may search multiple fields which have different indexing settings.