I'm writing this here because I really don't know what else I can do about that...
We have been using PowerApps in my company for more than a year now, and it worked just fine, but few months ago without any changes in the app or connections, it started to show time to time "Server Error" messages..
Recently, error messages show more details and I can see it's error code 502. It shows up sometimes on a label, sometimes on a Droplist, sometimes on a Button..
I have seen other posts but they are related to Flows & Sharepoint, and we don't use neither of those. We have a DirectQuery connection to our SQL Server database, using a Gateway (installed for Power BI but also used for PowerApps. Gateway status = connected, all ok).
This problem is really unconsistant, but I cannot say that this is someting Punctual, as it happens few times a day...
I attach error message from the PC. In this case it's a simple droplist to our SQL server: Distinct('[DB].[Table]';Name) (maybe 20 rows max in this table....)
If it persist, we will have to reconsider using PowerApps at all.