What is the most likely cause of toilet cistern leak?

[Gary111]

Hi, I have had to remove and replace my close coupled toilet, but it is now leaking underneath at the back.
I had to really push it to get the cistern back to the wall.

Any idea w

hat's the most likely cause please?

 

[Gary111]

PS it's leaking all the time, not just when flushed

 

[Deleted member 267285]

Probably the donut washer and or bolts not tight enough

 

[Deleted member 267285]

PS it's leaking all the time, not just when flushed

Your flush valve is likely letting by and the donut washer hasn’t seated properly or the through bolts aren’t correct or tight enough

 

[Gary111]

Thanks for your help