There are multiple solutions for this puzzle. A common tip I see from a lot of hanjie players and makers is to try playing your own puzzle before submitting it to make sure it is logical. Thank you for the puzzle!

How is this makeable??? Help needed, please !!!

Well this is just awful. No logic and multiple solutions. 15 attempts in and still no correct solution. You should never have to guess in these puzzles.

I must be on the same wavelength as Gavynyoyo as I managed to guess right first time!

Hints:

R1 - C1, C3, C5, C21, C23, C25
R2 - C6, C8, C10, C16, C18, C20
R3 - C1, C3, C5, C11, C13, C15, C21, C23, C25

Repeat this pattern on all sides to make a fully symmetrical border. Then the rest is easy to fill in.

Thank you Hungary Hippo !

Thanks a lot Hungary Hippo - without you I had given up...

Thank you Hungary Hippo !! How did you find out ? Only by try and error ?

Yes thanks, Hungary Hippo. I got the centre filled in but got stuck on the borders.

Borders a bit tricky, but nice design.