Options chain data not loading from Bloomberg

[JennyCon]

Code Sample, a copy-pastable example if possible

Import the pdblp wrapper

import pdblp

Create a BCon object

con = pdblp.BCon(debug=True, port=8194, timeout=5000)
con.start()

Fetch the Options Chain from Bloomberg and print it out

OPTChain = con.bulkref('CO1 COMDTY', flds='OPT_CHAIN')
print(OPTChain)

#### Problem description

For some reason Bloomberg is telling me that the field does not apply to CO1 COMDTY anymore which is strange as it worked yesterday.  Does anyone have any idea why?

 errorInfo = {
                        source = "19390:rsfrdsvc-slow1"
                        code = 9
                        category = "BAD_FLD"
                        message = "Field not applicable to security"
                        subcategory = "NOT_APPLICABLE_TO_REF_DATA"


#### Expected Output

#### Version Information

[paste the output of ``pdblp.__version__`` here below this line]
 errorInfo = {
                        source = "19390:rsfrdsvc-slow1"
                        code = 9
                        category = "BAD_FLD"
                        message = "Field not applicable to security"
                        subcategory = "NOT_APPLICABLE_TO_REF_DATA"