That's happening to short BTC addresses? Are they no more accepted?

During the frontend maintenance, today at 10:30Z, the pool started to reply with "Invalid BTC address" and drops the connection.

Check
https://nicehash.com/?p=miners&a=4&addr=1N9kZERoSUrg1pS4WKK75wwAjLAaymGYs
https://nicehash.com/?p=miners&a=0&addr=1puHcBX19JwCYTzTtPjRwHwjxPtRR95YT
https://nicehash.com/?p=miners&a=0&addr=1PTkxirE2VgnSAKqzQwek25Nt5WCSgm1R
https://nicehash.com/?p=miners&a=3&addr=1rZpjJoXCxYHJEuQ4R3nB1FdGNkrAima1
https://nicehash.com/?p=miners&a=0&addr=1Bhtdh47ieDHrcaGvek9EriGYoPpgihc1
https://nicehash.com/?p=miners&a=1&addr=1jCMLVX18JdXKjPumkuYS5QpBueMLj3vJ

Data and graph seems corrupted (and payments stopped)

--- edit ---
these addresses are pretty valid and were payed several times in the past, they are only 33 chars long instead or the more common 34 chars length.