Calc error " The link could not be updated"

I have a spreadsheet pulling in live currency prices from an external API. I have an odd error whereby I have identical code in two cells, but one fails and the other succeeds:
Cell one displays “The link could not be updated”
Cell two displays the desired exchange rate!

Any ideas?

can you attach the file with the links?

EDIT: I sorted the problem by copying data to a new row. I think I must have changed a parameter of one cell which caused the error. Thanks anyway Torreone.