Steps to reproduce

Not 100% sure. It consistently fails for some surveys, but consistently works for others (with fewer participants?). It's not immediately obvious what the problem is.

My hunch is:

• create a survey
• add > 10001 participants with valid emailaddresses and valid tokens (so they are eligible for an invitation)
• call invite_participants without specifying specific participants to invite (aTokenIds = null). I'm not sure if this will already fail. It might work
• call invite_participants again with aTokenIds = null. Probably error, because it returns information about the first 5k participants that already got an email without actually sending any new emails?

Alternative possibility:

• create a survey
• add > 10001 participants with valid emailaddresses, of which the first 5k are expired (or not valid yet)
• call invite_participants without specifying specific participants to invite (aTokenIds = null). I have a feeling this will fail

Expected result

Multiple things:

• I expect it to completely ignore participants that are not valid anymore or not valid yet. I don't expect those in the response at all, or at least let me specify whether i want to know about those.
• I expect the docs to mention something about a limitation to 5000 participants. Nice to have would be if that limitation was removed
• If there are more than some limit people to invite, i expect it to at least invite participants up to that limit. It should not matter if there are also more than that limit of expired/not valid yet/already invited participants. If there are 1000 expired participants and 6000 that are eligible for an invitation and the limit of emails to send if 5000, i expect 5000 emails to be sent, not just 4000 because there are 1000 irrelevant participants.

Actual result

• HTTP 500 response without an explanation of what's wrong

Also

• It seems to limit the result to 5000 participants, which is not mentioned anywhere in the docs. There seems to be no way around this without specifying specific participants?

Note: I have a feeling the same problem might occur under specific circumstances in remind_participants, but did not actively run into that. If you find the cause, please check if remind_participants is also affected