小程序生成二维码出现错误，提示以下问题什么原因？

MiniProgramError

Cannot read property '_src' of undefined

TypeError: Cannot read property '_src' of undefined

    at bl..e.useHardwareAccelerate [as drawImage] (eval at n.call.document (http://127.0.0.1:14008/remote-debug/runtime.js?devtools_ignore=true:1:14919), :2:1097717)

    at bl.r. [as drawImage] (eval at n.call.document (http://127.0.0.1:14008/remote-debug/runtime.js?devtools_ignore=true:1:14919), :2:1125864)

    at eval (weapp:///pages/ptIndex/ptIndex.js:654:21)

    at success (weapp:///utils/base64src.js:31:7)

    at eu (eval at n.call.document (http://127.0.0.1:14008/remote-debug/runtime.js?devtools_ignore=true:1:14919), :2:1123943)

    at a.success (eval at n.call.document (http://127.0.0.1:14008/remote-debug/runtime.js?devtools_ignore=true:1:14919), :2:1126088)

    at

    at Object.eval [as success] (eval at n.call.document (http://127.0.0.1:14008/remote-debug/runtime.js?devtools_ignore=true:1:14919), :2:113735)

    at a (eval at n.call.document (http://127.0.0.1:14008/remote-debug/runtime.js?devtools_ignore=true:1:14919), :2:939697)

    at eval (eval at n.call.document (http://127.0.0.1:14008/remote-debug/runtime.js?devtools_ignore=true:1:14919), :2:939880)