DF Sendgrid Webhook Issues

Sorry for the lack of info, but was wondering if anyone could help me troubleshoot an issue with the sendgrid event webbook.

DF 3.0 (OSS)
DF database SQLITE
API Service DB Postgres (same server as DF)
API permissions/role: FULL permissions as currently in DEV (i.e. PUT, POST, GET etc etc)
Service setup: pretty much default, host: 127.0.0.1, schema: public, allow upsert, enable cache etc

Error:

==> …/nginx/error.log <==

2020/02/02 02:41:05 [error] 1471#1471: *4957 FastCGI sent in stderr: “PHP message: REST Exception #1000 > Batch Error: Not all requested records could be created” while reading response header from upstream, client: x.x.x.x.x, server: xxx.xxx.com.au, request: “POST /api/v2/sendgrid/_table/activity_webhook?api_key=xxxxxxxxxxx HTTP/1.1”, upstream: “fastcgi://unix:/var/run/php/php7.2-fpm.sock:”, host: “xxx.xxxx.com.au”

I also get this in nginx log when it fails.

x.x.x.x - - [02/Feb/2020:02:43:59 +0000] “POST /api/v2/sendgrid/_table/activity_webhook?api_key=xxxxxx HTTP/1.1” 500 20642 “-” “SendGrid Event API”

Any help would be appreciated.