block submission failed with: invalid
hi, I am running some other pools for coins, and haven't seen this issue. I am testing running a DGB-Sha256 pool. I got some blocks, and received the following error:
submission failed with: invalid
please help
thanks

[2020-05-10 04:47:50.9361] [I] [dgb1] Detected new block 10805565 [POLL] 
[2020-05-10 04:47:50.9361] [I] [dgb1] Broadcasting job 
[2020-05-10 04:47:51.0433] [I] [dgb1] [0HLVKE7CBKGV8] Share accepted: D=31437.32 
[2020-05-10 04:47:51.2092] [I] [dgb1] [0HLVKE7CBKGVB] Share accepted: D=52005.232 
[2020-05-10 04:47:51.7166] [I] [dgb1] Submitting block 10805565 [0000000000000528137d8d06115ad99d75d31db4206e2f012b719806edff8bb9] 
[2020-05-10 04:47:51.7166] [W] [dgb1] Block 10805565 submission failed with: invalid 
[2020-05-10 04:47:51.7166] [I] [dgb1] [0HLVKE7CBKGVB] Share accepted: D=52005.232 