Antminer L3+ not able to connect

Hi all,

I have an Antminer L3+ which had been connected a while to prohashing but I saw constant drops and the Antminer connecting towards another mining pool just to test.
Right now, the Prohashing pool is back at the first spot (primary pool) but it does not connect anymore.

I (think) did not make any changes (except switching pools) but no connections are made anymore.
Anyone had this issue and knows what the workaround is?

My connection strings are:
Pool: prohashing.com:3333
username: energy263
pwd: n=asicminer

Anything I could improve?