There are a few different reasons why an order might be delayed. These are depending on the order stage.
The start of production seems late
If your order takes longer than expected to start production, it could be that the printing engineer is still analyzing the part. This can happen with complex geometries or orders that were placed using an unsuitable technology or material. In this case, once they know where the issue lies, they will be sure to reach out to you with a solution.
The order is in production for a bit longer than expected
If your order takes longer than expected to finish production and to be shipped, the reason behind this could be that the printer experienced a failed print. This is completely normal in the world of 3D printing and it does not mean that this is the end of your project. It just means that the error must be found, fixed, and then the print can be restarted. Naturally, this causes a delay.
Extensive shipping time
If your order was shipped but takes longer than expected to be delivered, then the explanation for this delay can only be given by the carrier service in charge of transporting and delivering your parcel. Usually, these delays are dependent on the current global situation, holidays in countries along the way, or resource shortages the carrier suffers temporarily. As the intended recipient of the parcel, they should provide you with all relevant information on its status. However, if you need help on that end, please feel free to reach out to the manufacturer via message and they will be happy to help.