Cant upload pics

2021.07.21

Unable to upload pictures to Marketplace. Error received below:
An error occurred at 7/21/2021 6:21:29 PM as follows

A potentially dangerous Request.Form value was detected from the client (ctl00$ctl00$mcp$MemberContentPlaceholder$fDescription="... cel from Shamanic Princess...").

at System.Web.HttpRequest.ValidateString(String s, String valueName, String collectionName)
at System.Web.HttpRequest.ValidateNameValueCollection(NameValueCollection nvc, String collectionName)
at System.Web.HttpRequest.get_Form()
at System.Web.HttpRequest.get_HasForm()
at System.Web.UI.Page.GetCollectionBasedOnMethod(Boolean dontReturnNull)
at System.Web.UI.Page.DeterminePostBackMode()
at System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)
at System.Web.UI.Page.ProcessRequest(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint)
at System.Web.UI.Page.ProcessRequest()
at System.Web.UI.Page.ProcessRequestWithNoAssert(HttpContext context)
at System.Web.UI.Page.ProcessRequest(HttpContext context)
at ASP.member_market_item_aspx.ProcessRequest(HttpContext context)
at System.Web.HttpApplication.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute()
at System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously)

I can’t upload any images either. I have reduced sizes to less than 800 kB, have converter to JPG> JPEG and back, no matter what I keep getting message that images can only upload JPG and nothing saves. I have to use images from my IOS cel phone, I don’t have another method right now.