Cannot download data from odk aggregate server

What is the problem? Please be detailed.
Installed ODK Aggregate server in Google Cloud and only recently not able to download the data exporting to csv file.

What ODK tool and version are you using? And on what device and operating system version?
I don't remember the version of the aggregate server but was installed last year around May or June 2018. Installed in google cloud application service

What steps can we take to reproduce the problem?

What you have you tried to fix the problem?

Anything else we should know or have? If you have a test form or screenshots or logs, attach here.
I have uploaded screen shots of the exported submissions page in the aggregate server and the google cloud app service error log. Hope this helps

Your App Engine instance is running out of memory. The short answer is to use Briefcase to download your data. The long answer is to upgrade Aggregate to the latest version and increase server size.

Thanks Yanokwa,

As this server is still accepting data from the field, only just now, when submitting data from ODK Collect, the following error is encountered: Error: Internal Server Error (500) at {server name}.

Please help!