The offer published, but not taken

I created and published the offer to buy BTC at a higher price then
the current BTC prioffer to buyce BUT no seller is there to accept the offer. is anything wrong I do with the trading ?

Sometimes there is even negative spread in Bisq, but usually this is because of different payment methods used by traders. Some traders just can’t use certain payment methods so can’t take some offers.

If you use popular payment method, then it just might be simply a matter of time that no one saw your offer.

I managed to take an existing offer to buy BTC (zelle).I am waiting for Blockchain confirmation
It is more than a day since. It looks something is wrong . Does the seller MUST be online ??

It could be just due to transaction congestion on the Bitcoin blockchain. You could try ViaBTC’s transaction accelerator service, just try to post the transaction id to their accelerator on the full hour before the free spots get filled.

If you want to insure your privacy and not get that bitcoin transaction linked to your IP you can use the Tor browser. Here is a link to that accelerator (https://pool.viabtc.com/tools/txaccelerator/)