What happens if I cannot submit the A1 form?
If you meet all the posting conditions while being posted abroad, you remain included in the social security system of the posting Member State, regardless of whether you have the A1 form (although you consequently cannot be included in the social security system of the receiving country).
However, if you cannot submit the A1 form as a posted worker, the receiving Member State in which you are temporarily working does not have proof that you meet the posting conditions. In such case, the authorities of the receiving Member State may decide that you must be included in the social security system of the receiving country. This means that you must pay national contributions, and fulfil all related administrative obligations. The A1 form may also be obtained retroactively, but getting your records in order, as you might imagine, costs a lot of time and money!