DYNAMIC_SERIES
What happened
Forge reads which series a strategy asks for before the run, so it can load only the data it needs. A series chosen in a way it cannot read, for example from a variable computed at run time, is refused.
What to do
Write the price field, the symbol or the timeframe in the file, or use a setting.
Example
text
strategy.py, line 42: d[...] takes a price field or a symbol written in the file, or a setting. [DYNAMIC_SERIES]The wording of the message depends on your file, and the code does not. An error stops the file from loading.