Uefa has described the commercial aspect of Scotland's bid to host matches at Euro 2020 as "inadequate".
The Scottish Football Association has bid for Hampden Park to host three group games and one knock-out match.
A Uefa report highlighted a lack of "clarity", but praised Glasgow's transport links and hotel accommodation as "impressive".
The SFA say they have re-iterated to Uefa that the commercial requirement would be fulfilled "in its entirety".
Euro 2020 will be held in 13 countries, with England, Republic of Ireland and Wales also vying to host matches.
Cardiff's Millennium Stadium and the Aviva Stadium have been proposed as venues while Wembley could host the final.
Glasgow recently hosted the 2014 Commonwealth Games, with Hampden used to showcase athletics and the closing ceremony.
|Stadiums bidding to host Euro 2020 matches|
|Baku Olympic Stadium, Azerbaijan||Traktar Stadium, Belarus||New stadium, Brussels||Ovcha Kupel Stadium, Bulgaria|
|Parken Stadium, Denmark||*Wembley Stadium, England||*Allianz Arena, Germany||New Puskas Ferenc Stadium, Hungary|
|Teddy Stadium, Israel||Stadio Olimpico, Italy||Philip II Arena, Macedonia||Amsterdam Arena, Netherlands|
|Aviva Stadium, Republic of Ireland||Arena Nationala, Romania||New Zenit Stadium, Russia||Hampden Park, Scotland|
|San Mames Stadium, Spain||Friends Arena, Sweden||Millennium Stadium, Wales||* bidding to host final|
Uefa's executive committee will vote on the host cities on 19 September - the day after the Scottish independence referendum.
The possible outcomes of the referendum are acknowledged in Uefa's report.
It says the legal aspects of Scotland's bid "may have to be re-assessed" if the country becomes independent.
"Scotland being part of the UK, the legal situation is mostly - but not entirely - identical to that of England and Wales," the report adds.
Cardiff's bid gets a generally favourable evaluation report, but inspectors point out fans would have to use airports in Bristol or even London.
Dublin receives one of the best evaluation reports among all 19 bidders while Wembley's bid is generally positive and similar to that of main rival for the final, the Allianz Arena in Munich.
However, the proposed fan zone outside of central London is rated as only "satisfactory" and plans for fan zones in other English cities are "very weak".
Munich's fan zone proposal is rated as "attractive", but plans for fan zones in other German cities were also rated "weak".
Wembley is regarded as the favourite after the German FA announced it may not push hard for Munich in order to concentrate on a bid to host the entire Euro 2024 tournament.