@kimounkisa Hi, it is still an issue lately. With my friends what we found to be working is the following:

• close FAF client completely
• change default browser (usually we use Firefox by default, and it seems to be causing the problem) to i.e. Edge
• delete the client.prefs file from C:\Users\yourName\AppData\Roaming\Forged Alliance Forever
• start FAF client, click on logon, and this time it should send you to your new default browser to logon with your FAF account.

Hope it works for others too.