The BN808 is not made by u-blox. The claim that it contains a u-blox GNSS receiver is also suspect since there are many fakes claiming legitimacy.
If the BN808 contains a bonafide, properly implemented u-blox M8 receiver, the Seaclear software is likely expecting NMEA v2 GPS messages while the BN808 is sending NMEA v4 GNSS messages.
There are many posts on how to resolve this; search for CFG-NMEA command in this forum.
But the more fundamental problem is the inability to connect with USB. You haven't indicated what Windows version... solutions vary depending on version.
If you are using Windows 10, then you must remove the location/sensor USB driver and imstall the simple CDC-ACM VCP USB driver, available on most u-blox Positioning product web pages under "documentation and resources"
The USB connection shows up as a virtual COM port like "COM4". Download the u-center software tool from u-blox website "Support" menu, -> "Evaluation Software". This will help verify your COM USB connection.
Refer to other forum entries on how to determine which u-blox receiver you have.
If you still can't get the USB to work, then contact the source from which you bought the product to get support and replacement.
If unsuccessful, then chalk this up as a learning experience and find a reputable supplier of puck/mouse GPS antenna products.
If the Seaclear software expects NMEA v2 messages, then consider a GPS antenna product based on u-blox 6 technology --older but works well and is compatible with older applications.
You might also check the Seaclear support forum for hints. My quick internet search for "seaclear" project puts it in the category of "old" software based on NMEA v2. But there may be updates. Try their forum.