Liverpool manager Jurgen Klopp has used a UEFA coaches' conference to call for change to the VAR system.
A host of leading European managers attended the summit at UEFA headquarters in Nyon, Switzerland, including Klopp and Manchester City rival Pep Guardiola.
Guardiola was left fuming after Liverpool's VAR-assisted 3-1 defeat of his side on Sunday, in which City had two penalty appeals rejected.
While Klopp was the beneficiary, the German insisted at Monday's summit the use of VAR had to be improved, a point he said he and Guardiola had agreed on after a discussion following Sunday's game.
"VAR can be improved, it can. It will never be 100 per cent accurate, everybody knows that. But there are a couple of things that are not right," Klopp was quoted as saying by The Sun newspaper.
"With VAR, handball, offside, it is clear we have to keep on improving.
"There were good ideas from Uefa (about) how we can sort things from the referees, so everybody is in on it.
"There is still space for mistakes. These things are done by human beings and none of us is perfect. Nobody is asking for perfection, you just want to have the right decisions."
Klopp also voiced his concerns over the increasingly-crowded fixture programme, saying: "The discussions on that are really important and we have to start them."
Also attending the summit were managers including Arsenal's Unai Emery, former Chelsea boss Maurizio Sarri, Ajax's Erik ten Hag, and Paris-Saint Germain's Thomas Tuchel.