How to Put the message using UOM (begin, commit, backout). getting error: 2012 MQRC_ENVIRONMENT_ERROR

import pymqi

queue_manager = 'QM1'
channel = 'DEV.APP.SVRCONN'
host = '127.0.0.1'
port = '1414'
queue_name = 'TEST.1'
conn_info = f'{host}({port})'

# Connect to the queue manager
qmgr = pymqi.connect(queue_manager, channel, conn_info)
queue = pymqi.Queue(qmgr, queue_name, pymqi.CMQC.MQOO_OUTPUT)
try:
    for rec in range(1,21):
        message = f"hello python {rec}"
        queue.put(message)
except Exception as err:
    print(f"(err)")
queue.close()
qmgr.disconnect()

When I did the PUT operation using the above code it worked as expected.

When I am trying to do the PUT operation using the below code. It is giving me an error saying FAILED 2012: MQRC_ENVIRONMENT_ERROR.

import pymqi

queue_manager = 'QM1'
channel = 'DEV.APP.SVRCONN'
host = '127.0.0.1'
port = '1414'
queue_name = 'TEST.1'
conn_info = f'{host}({port})'

# Connect to the queue manager
qmgr = pymqi.connect(queue_manager, channel, conn_info)
queue = pymqi.Queue(qmgr, queue_name, pymqi.CMQC.MQOO_OUTPUT)
pmo = pymqi.PMO()
pmo.Options = pymqi.CMQC.MQPMO_SYNCPOINT | pymqi.CMQC.MQPMO_FAIL_IF_QUIESCING

transaction = False
try:
    # transaction start
    qmgr.begin()
    # set the flag true after qmgr begin
    transaction = True  
    for rec in range(1,21):
        mqmd = pymqi.MD()
        mqmd.Version = pymqi.CMQC.MQMD_VERSION_2
        if rec == 9:
            raise Exception("Some Error occur")
        message = f"hello python {rec}"
        queue.put(message, mqmd, pmo)
    # commit the transaction if all message were successfully processed
    qmgr.commit()
except Exception as err:
    if transaction:
        # rollback the transaction if any error occur during the processing
        qmgr.backout()
finally:
    queue.close()
    qmgr.disconnect()

The MQRC_ENVIRONMENT_ERROR typically indicates a problem with the environment or configuration, rather than an issue with the code itself but where and what should I need to check?

IBM MQ's transactions (begin/commit/backout) should be used in conjunction with the MQOO_INPUT_EXCLUSIVE and MQOO_OUTPUT options. These options control how the queue is opened and dictate the ability to participate in transactions.

You are not using an external transaction manager, therefore, you cannot use the MQBEGIN MQ API call (i.e. qmgr.begin() ). Remove it and your code will be doing a local UOW.

Also, if you want the consumer application to be using a local UOW then add the following to your code plus the MQBACK & MQCMIT MQ API calls.

gmo = pymqi.GMO()
gmo.Options = pymqi.CMQC.MQGMO_SYNCPOINT | pymqi.CMQC.MQGMO_FAIL_IF_QUIESCING