I tried to do it via Explorer browser, but I couldn't even type my nationality into the boxes.

 

Then I tried Android app via my mobile phone.  I could fill in the details.  Wow !  However, when I clicked the "register" button, it would take years and years, and the system would return with a "time out error".

 

Has anyone had any success with registering an online account for TM 30 reporting ?

I managed to register a couple of years ago on my local immigration website, and did do several TM.30 reports for myself.  It was all  in Thai, so unless you read Thai, you might need someone  to help you. Unless it has changed.

I recall it was very clunky.

 

My local main office is:  http://suratimmigration.go.th/extranet/

 

My local immigration office eventually stapled a pice of paper into my passport saying something like 'Mr. X has notified us of his address.'

Now I no longer have to do the reports each time I return to Thailand.

 

The only other thing I can suggest  is to try another  browser.