I checked the apiserver.log file in /opt/clearml/logs and this appears to be the related error when I try to publish an experiment:

` [2021-06-07 13:43:40,239] [9] [ERROR] [clearml.service_repo] ValidationError (Task:8a4a13bad8334d8bb53d7edb61671ba9) (setup_shell_script.StringField only accepts string values: ['container'])
Traceback (most recent call last):
File "/opt/clearml/apiserver/bll/task/task_operations.py", line 325, in publish_task
raise ex
File "/opt/clearml/apiserver/bll/task/task_operations.py", line 301, in publish_task
task.save()
File "/usr/local/lib/python3.6/site-packages/mongoengine/document.py", line 392, in save
self.validate(clean=clean)
File "/usr/local/lib/python3.6/site-packages/mongoengine/base/document.py", line 450, in validate
raise ValidationError(message, errors=errors)
mongoengine.errors.ValidationError: ValidationError (Task:8a4a13bad8334d8bb53d7edb61671ba9) (setup_shell_script.StringField only accepts string values: ['container'])

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
File "/opt/clearml/apiserver/service_repo/service_repo.py", line 277, in handle_call
ret = endpoint.func(call, company, call.data_model)
File "/opt/clearml/apiserver/services/tasks.py", line 1131, in publish_many
ids=request.ids,
File "/opt/clearml/apiserver/bll/util.py", line 122, in run_batch_operation
results.append((_id, func(_id)))
File "/opt/clearml/apiserver/bll/task/task_operations.py", line 329, in publish_task
task.save()
File "/usr/local/lib/python3.6/site-packages/mongoengine/document.py", line 392, in save
self.validate(clean=clean)
File "/usr/local/lib/python3.6/site-packages/mongoengine/base/document.py", line 450, in validate
raise ValidationError(message, errors=errors)
mongoengine.errors.ValidationError: ValidationError (Task:8a4a13bad8334d8bb53d7edb61671ba9) (setup_shell_script.StringField only accepts string values: ['container']) `