The cash-strapped authority spent around £280,000 to send top civil servants and councillors to three MIPIM events in the South of France – two of which were cancelled due to Covid.
An independent auditor's report, commissioned by the Conservative-run council, has highlighted a series of governance failings linked to the authority's involvement with the event.
The report, which has not yet been made public, claims that poor project management by officers led to cash being paid to Associate Events without "due process" being followed.
The council says it is "following legal processes" in a bid to recover costs associated with the cancelled events in 2020 and 2021.
Councillor Patrick Harley, leader of Dudley Council, said he was "very disappointed" in the way senior officers had managed the process and that there would be "consequences" once it was completed.
He told the Express & Star: "This is about making sure we do things differently in future, and that may mean some new processes are put in place for officers.
"The report we commissioned ourselves through independent auditors highlights some areas where there are lessons to be learnt in relation to governance processes around the conference attendance which was postponed twice due to the Covid-19 pandemic.
"As we work hard to bring in millions of pounds of investment we are also committed to providing value for money and we are continuing to follow legal processes to recover some of the costs incurred in relation to the MIPIM arrangements dating back to 2019."
Councillor Harley maintained that the council's attendance at the event was justified as it had put them in contact with "really big players" who were looking to invest in the borough.
"Advanced discussions are already taking place with one business around a £40 million housing development which could see up to 200 homes built on the site of the former leisure centre in Dudley," he said. "This, and talks with other key investors, will help add to the £1 billion worth of regeneration projects which are already gathering pace in the borough.
"Through our contacts from attending MIPIM we are also progressing talks with three developers/investors which if they get over the line will mean several hundred million pounds worth of added growth and developments for our borough.
"This will be investment not only in Dudley town centre but also Brierley Hill and Stourbridge and could ensure a pipeline of investment and development for the next 15 years."
MIPIM is regularly attended by councils from across the region, who claim it offers opportunities to draw in external investment.
Dudley Council did not attend this year's event from March 14-17, which featured representatives from Sandwell Council, Walsall Council and Wolverhampton Council.