I'm having exactly the same problem. For ages the reg I have for simmarket worked fine. Havent played my flight sim for ages so did a new install today and now FScommander wont accept my simmarket registration details.
1. FSX SE
2 FSUIPC4 4.948
3. Latest Version of FS Commander downloaded from your website
4. Running windows 10 upgraded from Win 7
I can send you in a pm my simmarket registration details if you require. I can also provide you with the simmarket order number and date of purchase.
When I try to enter simmarket reg details into fscaommander reg screen it says the details are incorrect.
Please cna you help me.
Thanks Jason Shephard