Live data postings occasionally fails with no reply, alternatives to catch-up?

Hello, I’m investigating the issue where occasionally there are bursts of missing data in the 5-minute live data upload, which is http posted with my own esp8266 HW & SW, using esp8266 api and Arduino libraries. Data is posted to with Content-Type=application/x-www-form-urlencoded. I have not yet invested in getting TLS to work on this platform, to use the HTTPS secure connection.

Normally, all is well. But during the day there are several occasions where a normal http post wait and retry doesn’t get an answer from Sometimes, several of the subsequent 5-minute instances do fail.
The software will wait for about 5s for a reply, and without reply, it will repeat the whole request for about 30 seconds. So there are usually 5 or 6 tries to connect and post data to PVO. Sometimes it succeeds and still get a http 200 response. BTW, my logging shows that there are never error responses, only ‘OK’ (200) or no-reply.

I suppose this is network related, maybe the server is too busy, which I suppose you and I can’t do anything about.

In an effort to not lose data, I have tried to include old data into newer messages, but apparently the server doesn’t accept the extra data points. I have read that there are auto uploaders that upload 4x 5-min data once every 20 minutes.
For example, when server doesn’t answer the 16:55 and 17:00 data, at 17:05, I http post:
That are 3 datasets in one message. The server answers OK, but in the log I only see the 17:05 data, not the other two.

Is there another way automatically to catch-up missing data?

Use addbatchstatus.jsp to send multiple datapoints

Thanks. That does the job. Now I can implement a retry and recovery mechanism when the PVO server is temporarily not reachable.