Pulpissimo- errors during FPGA synthesis.

[plumerai]

I am trying to synthesize Pulpissimo with Vivado 2019.2 for nexys A7-100. I get the following errors:

Code:

[Place 30-69] Instance i_pulpissimo/pad_frame_i/padinst_bootsel/iobuf_i/IBUF (IBUF driven by I/O terminal i_pulpissimo/pad_frame_i/padinst_bootsel/iobuf_i/IO) is unplaced after IO placer
[Place 30-68] Instance i_pulpissimo/pad_frame_i/padinst_bootsel/iobuf_i/IBUF (IBUF) is not placed
[Place 30-99] Placer failed with error: 'IO Clock Placer failed'
Please review all ERROR, CRITICAL WARNING, and WARNING messages during placement to understand the cause for failure.
[Common 17-69] Command failed: Placer could not place all instances

I didn't modify a bit after cloning the repo.