Using SGP 1.40.0, Api 1.5.0 and Spigot 1.16.1 the method ShopGuiPlusApi.getPlugin().getPlayerManager().getPlayerData(player); throw a NoSuchMethodError, I have checked the code of SGP and the methods are different. On the api you need to pass a Player object while on SGP the method uses OfflinePlayer.
Using SGP
1.40.0, Api1.5.0and Spigot1.16.1the methodShopGuiPlusApi.getPlugin().getPlayerManager().getPlayerData(player);throw aNoSuchMethodError, I have checked the code of SGP and the methods are different. On the api you need to pass a Player object while on SGP the method uses OfflinePlayer.